Humidity variations spanning the ‘Little Ice Age’ from an upland lake in southwestern China

Abstract

A number of archives that span the past ~2000 years suggest that recent variability in hydroclimatic conditions that are influenced by the Asian monsoon in China are unusual in the longer term context. However, the lack of high-resolution precipitation records over this period hampered our ability to characterize and constrain the forcing mechanism(s) of the recent humidity variations. Here, we present the ratio of hematite to goethite (Hm/Gt) derived from the semiquantitative evaluation of the diffuse reflectance spectroscopic analysis as a reliable and effective precipitation proxy to reconstruct the humidity variations during the past 1400 years deduced from Tengchongqinghai Lake sediments, southwestern China. Hm/Gt varied synchronously with variations of Chinese temperature reconstructed from the historical documents and sunspot activity index over the past 1400 years. Critical periodicities of ~450 and ~250 years show that solar activity is the dominant control on precipitation change on centennial scales. However, the relationship determined from Hm/Gt in this study contradicts the stalagmite δ¹⁸O interpretations from different regions of China, which exhibit a more complex precipitation pattern that is influenced by the strength of westerly jet in addition to the Asian monsoon. The increased westerly jet during the ‘Little Ice Age’ (LIA) caused a humid climate in southern China and dry conditions in northern and western China.

Keywords

Humidity variations Hm/Gt ratio ‘Little Ice Age’lake sediment Southwestern China

Introduction

The climate variations over the past 2000 years are critical for contextualizing instrumental climate data in the longer term perspective, identifying anthropogenic influence on climate change, and simulating the course of future climate. It is therefore essential to reconstruct precipitation and temperature variations during the past two millennia. It has been recognized that the temperature variations in different climatic regions of China are broadly synchronous with those over the Northern Hemisphere (Ge et al., 2013; Yang et al., 2002). Nevertheless, the precipitation variations reconstructed from numerous archives, such as historical documentations, tree ring, stalagmite and pollen, revealed distinct centennial-scale variations and regional differentiations over the past 2000 years (Chen et al., 2015; Wang et al., 2001a; Zheng et al., 2014; Zhou et al., 2011 and reference therein; Yang et al., 2016). The humid/dry frequency derived from historical documents suggested that there is no uniform spatial pattern of rainfall in warm and/or cold climatic intervals during the past 2000 years (Chen et al., 2015; Wang et al., 2001; Zheng et al., 2014; Zhou et al., 2011). Based on historical documents, Wang et al. (2001b) have clarified the spatial patterns of rainfall in eastern China into six types. They suggested that the spatial patterns of rainfall in eastern China could be identified as ‘Droughts along the middle and lower reaches of the Yangtze River, floods to the north and the south of it’ and ‘Droughts in the south of the Yangtze River and floods in the north of it’ during the ‘Little Ice Age’ (LIA) (Wang et al., 2001b). The pattern of a North–South mode was suggested to dominate the Yangtze River. Zhou et al. (2011) analyzed the flood/dry frequency derived from history documents, and suggested that a relatively wetter climate dominated southern China while a relatively drier in the Yellow River valley during LIA. After synthesizing the most up-to-date and comprehensive proxy moisture/precipitation records during the past 1000 years in arid Central Asia and monsoonal Asia, Chen et al. (2015) proposed that there exists not only a ‘North–South’ mode of precipitation change in monsoonal eastern China but also a ‘West–East’ hydroclimatic dipole mode in mid-latitude Asia during the ‘Medieval Warm Period’ (MWP) and LIA.

The precipitation in southwestern China is mainly controlled by the southwest monsoon, and the spatial patterns of precipitation changes in southwestern China have been attracting growing interest (Chen et al., 2014; Li et al., 2018; Peng et al., 2019; Tan et al., 2018; Zhang et al., 2015). What are the spatial patterns of precipitation changes in southwestern China? Do the spatial patterns of precipitation in monsoonal eastern China during the past 2000 years also exist in southwestern China? These questions continually arose and high-quality records were required to shed light on the spatial patterns of precipitation changes in southwestern China. The sediments from Tengchongqinghai (TCQH) Lake and Xingyun Lake in southwestern China show that dry climate was predominant during the LIA (Chen et al., 2014; Li et al., 2018; Xiao et al., 2015; Zhang et al., 2015); however, a humid LIA was documented in Erhai Lake and Lugu Lake, which are located 176.2 and 367.3 km to the northeast, respectively (Sheng et al., 2015; Xu et al.,2014, 2015). Whether such apparent spatial differences in precipitation result from the uncertainty of proxies or reflect the geographical influence on atmospheric circulation still remain unclear. To better understand the climate changes during the LIA, more refined proxies of effective precipitation are required.

A series of studies suggested that hematite and goethite in soils and sediments provide a reliable precipitation proxy based on their opposite formation conditions and competitive formation mechanisms (Abrajevitch et al., 2009; Cornell and Schwertmann, 2003; Viscarra Rossel et al., 2010; Yapp, 2001). The reconstructed hematite and goethite ratios (Hm/Gt) from loess deposits and marine sediments have been successfully used to reflect the variations in effective precipitation (Balsam et al., 2004; Cornell and Schwertmann, 2003; Hao et al., 2009; Harris & Mix, 1999, 2002; Ji et al., 2004; Zhang et al., 2007). Here, we present a continuous and high-resolution Hm/Gt record from sediments in TCQH Lake, southwestern China to discuss the spatial pattern of precipitation during the past 2000 years. The linkage of the rainfall pattern to the solar activity and their possible mechanisms are also discussed.

Geological setting

Lake TCQH is an almost completely closed crater lake located in Tengchong County of Yunnan province, southwestern China (25°08′06″N–25°07′44″N, 98°34′11″E–98°34′26″E, elevation ca. 1885 m) (Figure 1a). A detailed description of the geological and geographical settings can be found in Peng et al. (2019). In brief, the lake water is mainly fed by precipitation. The mean annual air temperature is approximately 14.7℃ and the annual precipitation is about 1506 mm with an average of 19.9 mm in January and 291.3 mm in July (Li et al., 2018). Most of the total rainfall (75%) occurs during May to September (Peng et al., 2019). The terrestrial vegetation around the lake consists mainly of evergreen Quercus, Castanopsis, Lithocarpus, and Pinus (Li et al., 2018; Wang et al., 2002; Zhang et al., 2015) (Figure 1b).

Figure 1.

(a) Geographical location of the Tengchongqinghai Lake (TCQH, red star) and other sites of Wanxiang Cave (WX, Zhang et al., 2008), Huguang Maar (HGY, Zeng et al., 2012), Lugu Lake (LG, Sheng et al., 2015), and Jhumar Cave (JHU, Sinha et al., 2011) (orange solid circle indicates a dry LIA and blue solid circle indicates a wet LIA). (b) A photograph of the Tengchongqinghai Lake. (c) The sites of our cores.

Methods

Sampling

Five short gravity cores (named TCQH-1, TCQH-2, TCQH-4, TCQH-5, and TCQH-6) were drilled from the lake bank to the center with water depths varying from ~1 to 5.7 m (Figure 1c). TCQH-4 (25°7′59.03″, 98°34′20.32″) is the longest (144 cm) among the five cores. Three plant remains (tree branches or leaves) in TCQH-4 (at depths of 19, 59, and 107 cm, respectively) were collected for accelerator mass spectrometer radiocarbon ¹⁴C (AMS ¹⁴C) dating at Beta Analytic Testing Laboratory, US (Table 1). The age model established by linear interpolation shows that the age of the bottom sediments is 653 cal. yr AD, and thus TCQH-4 could document climatic variations of the past 1400 years.

Table 1.

AMS radiocarbon dates from Tengchongqinghai Lake (core TCQH-4).

Laboratory ID	Sample ID	Depth/cm	Material	Conventional radiocarbon age (cal. BP)	Percentage of modern carbon	Calibrated age (cal. AD)
Beta-487041	TCQH-4-1	19	Plant material		116.69 ± 0.44 pMC	1988–1990^a
Beta-494122	TCQH-4-2	59	Plant material	460 ± 30	4.43 ± 0.35 pMC	1412–1468^b
Beta-507829	TCQH-4-3	111	Plant material	1090 ± 30	87.31 ± 0.33 pMC	892–1014^b

Age was calibrated by the percent modern carbon using high probability density range method.

Age was calibrated by conventional radiocarbon age using high-probability density range method.

The cores were mainly composed of homogeneous silty clay, and the color varies slightly from light dark gray to dark gray with changing organic matter content. The volcanic breccia was observed from a depth of 35 cm from the top of TCQH-2 core. The cores are continuously sampled by pushing in plastic cubes (8 cm³) for environmental magnetism analysis. A total of 213 cube samples were collected, that is, 39, 25, 72, 46, and 31 for each core, respectively. The bulk samples were also collected at the same resolution.

Magnetic measurement

The low-field volume magnetic susceptibility (κ) was first measured at a frequency of 976 Hz with a Kappabridge on all specimens. The following magnetic measurements were only performed on cube samples of TCQH-4. Anhysteretic remanent magnetization (ARM) was imparted in a 100 mT alternating field with a superimposed 50 μT direct bias field using an alternating field demagnetizer anhysteretic and pulse magnetizer (LDA5/PAM1), and then measured on a Spinner Magnetometer JR6A. Isothermal remanent magnetism (IRM) was induced in a sequence of magnetic fields of increasing value up to 1 T. The IRM induced from the 1 T field is referred to as saturation isothermal remanent magnetization (SIRM). Measurements of all the SIRM were performed with a Spinner Magnetometer JR6A.

Hysteresis loops were measured on bulk samples of TCQH-4 using Princeton Measurements Corporation MicroMag 3900 vibrating sample magnetometer (VSMs). Coercivity (H_c) were obtained after diamagnetic and paramagnetic corrections. Remanence curves were measured by current demagnetization of 0 T back to −0.5 T, and remanent coercivity (H_cr) and isothermal remanent magnetization −300 mT (IRM_−300mT) were obtained by remanence curves. The hard fraction of IRM (HIRM) was defined as 0.5 × (IRM_1T + IRM_−300mT) and it is equivalent to the relative amount of hematite. The relative amount of goethite was defined as the difference in remanent magnetization under 1 T and 2 T fields.

In order to identify the type of magnetic materials in sediment, temperature-dependent susceptibility (χ–T) curves were measured on four representative cube samples of TCQH-4 using a Kappabridge MFK1-FA magnetic susceptibility meter from room temperature to 700℃ in an argon environment with frequency of 976 Hz. First-order reversal curves (FORCs) were measured on their bulk samples on VSMs, and the FORC diagrams were calculated from 180 FORCs using the FORCinel software version 1.18 (Harrison and Feinberg, 2008).

Diffuse reflectance spectrophotometry

The diffuse reflectance spectroscopic (DRS) analysis was measured on bulk sample of TCQH-4 to identify and semi-quantify the hematite and goethite. The pretreatment and analysis test followed the procedures described by Deaton and Balsam (1991) and Torrent and Barrón (2008). The dried bulk samples were first grinded under 200 mesh using an agate mortar and then the powder samples were put on a rectangular glass (7 cm × 4 cm × 2 mm) and made into slurry with ultrapure water. Then it was smoothed and dried at air temperature and analyzed on a Perkin-Elmer Lambda 950 spectrophotometer with a diffuse reflectance attachment. Data from the spectrophotometer were recorded at 0.5-nm intervals from 350 to 800 nm. The raw reflection curve was transferred into a second-derivation curve using the Kubella–Munk theory and mathematical method. The amplitudes of the characteristic bands in the second-derivation curve were used in the semiquantitative analysis of goethite and hematite.

Results

As is illustrated in Figure 2, TCQH-1, TCQH-4, TCQH-5, and TCQH-6 cores show the same range of volume magnetic susceptibility (0~50 ×10⁻⁶ SI) (Table S1). The magnetic susceptibility of the TCQH-2 core (~400 ×10⁻⁶ SI) is eight times that of other cores, possibly affected by the volcanic breccia. However, five cores are correlated well using the volume magnetic susceptibility, which denotes that the sediments possess common depositional features (Figure 2).

Figure 2.

Volume susceptibility records compared with other cores in this study. (a) TCQH-1 core. (b) TCQH-2 core. (c) TCQH-5 core. (d) TCQH-4 core. (e) TCQH-6 core.

All the loops of TCQH-4 tend to close before 500 mT and have a slight wasp-waisted shape, suggesting the presence of soft and hard components (Figure 3). It is consistent with the ranges of H_cr (26–72 mT) and H_c (9–16 mT). The χ–T curves display a remarkable decrease near 580°C indicating the presence of magnetite (Figure 3). A slight decreasing trend was also observed from the room temperature to near 180°C in the χ–T curves (Figure 3), suggesting the possible presence of goethite (Liu et al., 2012). The prominent valleys at ~415 and 535 nm wavelengths in the second derivative curves of DRS of all samples proved the presence of goethite and hematite (Figure 4).

Figure 3.

(a) Representative hysteresis loop (corrected for paramagnetism). (b) Magnetic grain size follows Dunlop (2002) of sample collected at variable depths. (c) χ–T curves for representative samples, where the red curves represent the heating curves. (d) FORC diagram for selected samples.

Figure 4.

The second derivative curves for selected samples (I₄₁₅ and I₅₄₀ are the amplitudes of these characteristic bands are measured as the difference between the minimum at the band and the next associated maximum at a longer wavelength in the derivative curves).

ARM, SIRM, κ, and ARM/SIRM ratios of TCQH-4 are shown in Figure 5 (Table S2). Hm and Gt concentrations and Hm/Gt ratios derived from the semiquantitative evaluation of DRS (Hm/Gt_(DRS)) in Figure 5 (Table S3). Although ARM is more susceptible to fine magnetic grains, numerous researches showed that ARM may be served as a proxy, indicating the fraction of SD particles in samples (Creer and Morris, 1996; Evans and Heller, 2003; Liu et al., 2012; Wang et al., 2001). The concentration parameters ARM, SIRM, and κ show that the concentrations of magnetic materials in TCQH-4 are stable in sediments below 103 cm. After that, the concentrations increase sharply. Apparently, increased Hm and Gt concentrations can be observed at the same section (Figure 5). However, the DRS-derived Hm/Gt ratios are relatively lower below 103 cm relative to the more recent part of the record. A similar trend can also be observed in the Hm/Gt ratios measured by environmental magnetism (Hm/Gt_(Mag)) (Figure 6). Meanwhile, the grain size parameter ARM/SIRM ratios show larger values (>0.05) below 103 cm while relatively stable values (~0.025) above 103 cm, which suggests that magnetic materials above 103 cm have relatively larger grain sizes to those below 103 cm. The varied grain sizes of magnetic mineral were also illustrated in the Day-plot (Figure 3). The Day-plot and FORC diagrams indicate that the magnetic mineralogy varied from PSD to SP-SD with depth (Figure 3).

Figure 5.

Down-core variations of magnetic and DRS parameters. (a) TCQH-4 Core photograph. (b) Volume susceptibility (κ). (c) Anhystere remanent magnetization (ARM). (d) Saturation isothermal remanent magnetization (SIRM). (e) ARM/SIRM. (f) Estimated content of hematite. (g) Estimated content of goethite. (h) Hematite/goethite (Hm/Gt).

Figure 6.

The Tengchongqinghai Lake humidity record compared with other records. (a) Hm/Gt record from magnetism parameters (navy blue solid line, smoothed by a 5-point adjacent average). (b) Hm/Gt record from DRS data (orange solid line, smoothed by a 5-point adjacent average). (c) Ensemble temperature reconstructions of China (Ge et al., 2013). (d) The stalagmite δ¹⁸O record of Dandak Cave (Sinha et al., 2007; blue solid line; smoothed by a 5-point adjacent average) and Jhumar Cave (Sinha et al., 2011, green solid line; smoothed by a 5-point adjacent average). The gray dashed lines are raw data records.

Discussion

Hematite/Goethite ratio as a proxy for effective precipitation proxy

The minerals hematite and goethite commonly occur in sediments and soils (Kämpf and Schwertmann., 1983; Schwertmann and Murad, 1983; Schwertmann, 1988). Hematite can be derived from several processes, such as ferrihydrite by a dehydration-rearrangement process and thermal dehydration from goethite (Jiang et al., 2012), whereas goethite mainly forms directly from any Fe source via solution and accumulates at the expense of hematite and maghemite through the dominance of rainfall-driven processes (Ji et al., 2004; Long et al., 2011; Zhang et al., 2007). Indeed, hematite and goethite formations are favored by opposite climate conditions and their formation processes are competitive (Schwertmann, 1988). Generally, goethite is favored by moist and cold conditions while hematite is favored by warm and dry conditions (Ji et al., 2004; Zhang et al., 2007). The rate of hematite to goethite, therefore, is mainly related to moisture variation in soil, and in turn to rainfall variation (Abrajevitch et al., 2009; Cornell and Schwertmann, 2003; Schwertmann, 1988). Significant correlations between the relative abundance of Hm and Gt and rainfall were observed in some studies (Hyland et al., 2015; Long et al., 2011). For example, the Hm/(Hm + Gt) ratios in a saprolitic ferralsol transect on Hainan Island, South China show a corresponding decrease as the rainfall increases (Long et al., 2011). The literature-derived and measured goethite-hematite (Gt/Hm) ratios of 70 modern soils from global sites reveal a significant positive correlation with the mean annual precipitation, with higher proportions of goethite versus hematite in a wetter state, and vice versa (Hyland et al., 2015). By recovering hematite and goethite from a variety of sediments, for example, marine sediment and Chinese loess (Hao et al., 2009; Ji et al., 2004; Zhang et al., 2007), some scientists used hematite and goethite concentrations, as well as their relative abundances, to reflect the variations in effective precipitation (Abrajevitch et al., 2009; Balsam et al., 2004; Cornell and Schwertmann, 2003; Hao et al., 2009; Harris & Mix, 1999, 2002; Ji et al., 2004; Long et al., 2011; Lyons et al., 2014; Zhang et al., 2007). For instance, Ji et al. (2004) used DRS to derive the Hm/Gt ratios from two sections in Chinese loess to reconstruct dry/humid patterns over central China during the last glacial–interglacial cycle. Using the Hm/Gt ratios in marine sediment from South China Sea, Zhang et al. (2007) produced the long-term variations in Asian monsoonal rainfall during the past 600 kyr. They suggested that the Hm/Gt ratio can be a reasonable precipitation proxy (Ji et al., 2004; Zhang et al., 2007).

In Lake TCQH, the process and environment of formation, transportation, and deposition of magnetic minerals appear to be related to rainfall variations. The magnetic property of magnetic minerals in five cores from Lake TCQH reveals great similarities, with relatively higher concentrations in sediments above 103 cm relative to these at the rest section (Figure 2). In addition, all cores, except TCQH-2, have almost the same ranges of κ. This means that the magnetic properties are largely controlled by the input of detrital, and finally by rainfall variations. Tengchong region has very high annual precipitation with a long rainy season. This not only results in a rapid formation of weathering minerals but also a rapid transportation of these weathering products into Lake TCQH. Consequently, in situ produced iron oxides that have been balanced with the climate in the Tengchong region are rapidly delivered to Lake TCQH. Therefore, the rainfall signal is well preserved in the Hm/Gt record.

Centennial-scales humidity variations during the past 1400 years

Over the past 1400 years, the Hm/Gt ratios suggest that two extremely dry periods at TCQH Lake occurred from AD 1065 to 1200 and from AD 1300 to 1750, corresponding to late-MWP and the LIA, respectively, and a wet period occurred from AD 653 to 1065, corresponding to the early MWP (Figure 6). This implies that the climate was humid and then turned to dry during the MWP and the climate was dry during the LIA in southwestern China. The overall trend of humidity variations in TCQH-4 is consistent with the temperature changes over the past 2000 years in China (Ge et al., 2013) and the Indian monsoon variations recorded by stalagmite δ¹⁸O data from Jhumar and Dandak Caves in Central India (Sinha et al.,2011, 2007) (Figure 6), suggesting a warm/wet-cold/dry pattern of climate over the past 1400 years in southwestern China.

Solar radiation was suggested to be one of the main factors influencing climate variation in monsoonal China during the Holocene (Jiang et al., 2017; Perry and Hsu, 2000; Wang et al., 2005). We separate the different components of the Hm/Gt_(DRS) ratios using Singular Spectrum Analysis–MultiTaper Method (SSA-MTM). The analyses were performed using the SSA-MTM toolkit freeware (Ghil et al., 2002). Three components were extracted. Significant centennial-scale cycles are clearly observed in PC2 and PC3 (Figure 7), although there are no significant cycles in PC1. Moreover, the variations in PC3 are similar to the variations of sunspot activities index (Solanki et al., 2004). Power spectrum analyses (Schulz and Mudelsee, 2002) of PC2 and PC3 have also revealed significant periodicities of 450 and ~250 years, which are consistent with the periodicity of solar activity (Agnihotri et al., 2002; Masarik et al., 2001; Stuiver and Braziunasm, 1993) (Figure 8). The continuous wavelet power spectrum (Grinsted et al., 2004) also shows these periodicities (Figure 9). We further apply the cross wavelet transform (XWT) and squared wavelet coherence (WTC) between Hm/Gt, PC3, and sunspot. The XWT and WTC results also show an in-phase relationship between Hm/Gt, PC3, and the sunspot index (Figure 9). The 450 and ~250-year periodicities have been recognized in monsoon documents of China during the Holocene (Cosford et al., 2008; Dykoski et al., 2005). This analysis suggests that solar activity had important influences on the regional precipitation in southwestern China during the past 1400 years.

Figure 7.

SSA analysis of Hm/Gt ratios and compared with sunspot record (Solanki et al., 2004). (a) Sunspot record. (b) PC3 of the Hm/Gt ratio. (c) PC1 and PC2 of the Hm/Gt ratio.

Figure 8.

MTM and power spectrum analysis of Hm/Gt PC2 and PC3 record.

Figure 9.

(a, b) The continuous wavelet power spectrum of standardized Hm/Gt, PC3, and sunspot index. (c, d) Cross-wavelet transform of the standardized Hm/Gt, PC3 and sunspot index time series. The relative phase relationship is shown as arrows (with in-phase pointing right, anti-phase pointing left). (e, f) Squared wavelet coherence between the standardized Hm/Gt, PC3 and sunspot index time series. The thick black contour designates the 5% significance lever against red noise and the cone of influence (COI) where edge effects might distort the picture is shown as a lighter shade.

The spatial differences of precipitation in southwestern China

According to our Hm/Gt_(DRS) records, the climatic condition was relatively dry during the LIA (Figure 10). Significant regional differences in hydrological conditions were observed across monsoonal China during the LIA (Figure 10). For example, the speleothem record from Wanxiang Cave documented a dry LIA in northern China (Zhang et al., 2008), while the sediment from Huguang Maar showed a wet LIA in southern China (Chu et al., 2002; Zeng et al., 2012) (Figure 10). A ‘south flood-north drought’ trend was the commonly spatial pattern of hydroclimatic changes during the LIA in monsoonal eastern China (Qian and Lin, 2005; Zheng et al., 2014). By analyzing the 63-site yearly dry/wet index derived from historical documents, Zheng et al. (2014) found that flood dominated the east of 105°E while drought was dominant its west part during the LIA. They proposed that there also exists an ‘east flood-west drought’ pattern during the LIA in monsoonal eastern China (Zheng et al., 2014). It is worth noting that the ‘east flood-west drought’ can also be observed in the monsoonal southern China during the LIA, with a wet LIA in coastal southern China, with a dry LIA in southwestern China (Chen et al., 2019; Chen et al., 2015), although some lakes sediments including Xingyun Lake (Chen et al., 2014), Erhai Lake (Xu et al., 2014, 2015), and Lugu Lake (Sheng et al., 2015) in southwestern China displayed a wet LIA. Obviously, the dry LIA deduced from our Hm/Gt_(DRS) record is consistent with the east–west mode. On centennial timescale, therefore, we proposed the possibility of a relatively dry condition in southwestern China during the LIA.

Figure 10.

The Tengchongqinghai Lake humidity record compared with other records. (a) The stalagmite δ¹⁸O record of Wanxiang Cave (Zhang et al., 2008). (b) Hm/Gt from this study. (c) The grain size record of Lugu Lake (Sheng et al., 2015). (d) TOC record of Huguangyan maar Lake (Chu et al., 2002).

The asynchronous variations in humidity in monsoonal southern China are unlikely to be caused by the anti-phase relationship of southeast and southwest monsoons (Hong et al., 2005), because speleothem δ¹⁸O records from monsoonal China and India documented weak summer monsoon intensity during the LIA (Sinha et al., 2011; Zhang et al., 2008). Numerous studies suggested that the ‘south flood-north drought’ trend in monsoonal eastern China was caused by the changes in the timing and duration of the EASM intraseasonal stages (i.e. spring, pre-Meiyu, Meiyu, and midsummer), and in turn were controlled by the south–north transition of the Westerly jet relative to the Tibetan Plateau (Hsu and Lin 2007; Hsu and Liu 2003; Chiang et al., 2017; Zhang et al., 2018). The seasonal migration of the maximal westerlies from south of the plateau to the north marked the onset of Meiyu, resulting in enhanced rainfall in the Yangtze River Valley, while the migration of westerlies away from the northern edge of the plateau marked the end of Meiyu (Chiang et al., 2017; Zhang et al., 2018). Then persistent rainfall would occur in northeastern China and southeastern China (Chiang et al., 2017). The relatively strong westerly jet was observed during the LIA (An et al., 2012; Mayewski et al., 1997). It would delay the seasonally northward shift of the westerly jet, and in turn delay the onset of Meiyu (Chiang et al., 2015), which would reduce rainfall in northern China, but enhance rainfall in central and southern China during the LIA (Tan et al., 2011). Moreover, during the cold phase, the strong westerly jet dominates the moisture transport of the whole Tibetan Plateau, resulting in reduced rainfall in the westerlies-dominated area and the Indian monsoon region (Zhang et al., 2017). The inverse humidity conditions recorded in our Hm/Gt (DRS) record and other lake sediments in southwestern China might have been caused by the complexity of the topography (e.g. plateau, and mountain) and the atmospheric circulation here.

Conclusion

The Hm/Gt deduced from TCQH Lake sediments in Southeast China was used to reconstructed precipitation variations in Tengchong for the past 1400 years. The combined Hm/Gt record suggests that the dry periods at TCQH Lake occurred from AD 1065 to 1200 and from AD 1350 to 1750, and the wet period was from AD 953 to 1065, during the past 1400 years. This shows that the MWP was wet and then became dry and the LIA was dry in Tengchong. Hm/Gt varied synchronously with the Chinese temperature reconstructed from the historical documents and sunspot activity index over the past 1400 years. The multiple periodicity analysis displayed significant ~450 and ~250-year cycles, suggesting that solar activity mainly controls precipitation changes in southwestern China. However, the humidity variations determined from Hm/Gt_(DRS) in this study contradicts these in other regions of China, which have a more complex precipitation pattern that is influenced by the strength of westerly jet in addition to the Asian monsoon. The solar activity and strong westerly jet may have an important influence on regional precipitation in southwestern China during the LIA.

Supplemental Material

Data_set_for_T.W._Zhang – Supplemental material for Humidity variations spanning the ‘Little Ice Age’ from an upland lake in southwestern China

Supplemental material, Data_set_for_T.W._Zhang for Humidity variations spanning the ‘Little Ice Age’ from an upland lake in southwestern China by Tingwei Zhang, Xiaoqiang Yang, Qiong Chen, Jaime L Toney, Qixian Zhou and Huahong Gao in The Holocene

Footnotes

Acknowledgements

The authors thank Fabienne Marret and two anonymous reviewers for their helpful and constructive reviews of the manuscript. Thanks are also due to Tingting Tao for sample collection. See supporting information for details of the data used in this study. The other data used are from the cited references.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article: This work is financially supported by the projects of NSFC (41672162, 41872217), the Natural Science Foundation of Guangdong Province (2018B030311064) and Guangdong Province Introduced Innovative R&D Team of Geological Processes and Natural Disasters around the South China Sea (Grant No. 2016ZT06N331).

ORCID iD

Tingwei Zhang

Supplemental material

Supplemental material for this article is available online.

References

Abrajevitch

Van der Voo

Rea

(2009) Variations in relative abundances of goethite and hematite in Bengal fan sediments: Climatic vs. diagenetic signals. Marine Geology 267: 191–206.

Agnihotri

Dutta

Bhushan

et al. (2002) Evidence for solar forcing on the Indian monsoon during the last millennium. Earth and Planetary Science Letters 198: 521–527.

Colman

Zhou

et al. (2012) Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka. Scientific Reports 2: 619.

Balsam

Chen

(2004) Climatic interpretation of the Luochuan and Lingtai loess sections, China, based on changing iron oxide mineralogy and magnetic susceptibility. Planetary Science Letters 223: 335–348.

Chen

Huang

et al. (2019) Westerlies Asia and monsoonal Asia: Spatiotemporal differences in climate change and possible mechanisms on decadal to sub-orbital timescales. Earth-Science Reviews 192: 337–354.

Chen

et al. (2014) Holocene vegetation history, precipitation changes and Indian Summer Monsoon evolution documented from sediments of Xingyun Lake, south-west China. Journal of Quaternary Science 29: 661–674.

Chen

Feng

et al. (2015) Hydroclimatic changes in China and surroundings during the medieval climate anomaly and little ice age: Spatial patterns and possible mechanisms. Quaternary Science Reviews 107: 98–111.

Chiang

Fung

et al. (2015) Role of seasonal transitions and westerly jets in East Asian paleoclimate. Quaternary Science Reviews 108: 111–129.

Chiang

Swenson

Kong

(2017) Role of seasonal transitions and the westerlies in the interannual variability of the East Asian summer monsoon precipitation. Geophysical Research Letters 44: 3788–3795.

10.

Chu

Liu

Sun

et al. (2002) The ‘Mediaeval Warm Period’ drought recorded in Lake Huguangyan, tropical South China. The Holocene 12: 511–516.

11.

Cornell

Schwertmann

(2003) The Iron Oxides: Structure, Properties, Reactions, Occurrences and Uses. Hoboken, NJ: John Wiley & Sons.

12.

Cosford

Qing

Eglington

et al. (2008) East Asian monsoon variability since the Mid-Holocene recorded in a high-resolution, absolute-dated aragonite speleothem from eastern China. Earth and Planetary Science Letters 275: 296–307.

13.

Creer

Morris

(1996) Proxy-climate and geomagnetic palaeointensity records extending back to ca. 75,000 BP derived from sediments cored from lago grande di monticchio, southern Italy. Quaternary Science Reviews 15(2-3): 167–188.

14.

Deaton

Balsam

(1991) Visible spectroscopy: A rapid method for determining hematite and goethite concentration in geological materials. Journal of Sedimentary Research 61: 628–632.

15.

Dunlop

(2002) Theory and application of the Day plot (Mrs/Ms versus Hcr/Hc) 1: Theoretical curves and tests using titanomagnetite data. Journal of Geophysical Research Solid Earth 107: EPM 4-1-EPM 4-22.

16.

Dykoski

Edwards

Cheng

et al. (2005) A high-resolution, absolute-dated Holocene and deglacial Asian monsoon record from Dongge Cave, China. Earth and Planetary Science Letters 233: 71–86.

17.

Evans

Heller

(2003) Environmental magnetism: Principles and applications of enviromagnetics. Springer: Elsevier.

18.

Hao

Zheng

et al. (2013) Temperature changes over the past 2000 yr in China and comparison with the Northern Hemisphere. Climate of the past 9: 1153–1160.

19.

Ghil

Allen

Dettinger

et al. (2002) Advanced spectral methods for climatic time series. Reviews of Geophysics 40(1): 1003–1000.

20.

Grinsted

Moore

Jevrejeva

(2004) Application of the cross wavelet transform and wavelet coherence to geophysical time series. Nonlinear Processes Geophysics 11: 561–566.

21.

Hao

Oldfield

Bloemendal

et al. (2009) The record of changing hematite and goethite accumulation over the past 22 Myr on the Chinese Loess Plateau from magnetic measurements and diffuse reflectance spectroscopy. Journal of Geophysical Research: Solid Earth 114: B12.

22.

Harris

Mix

(1999) Pleistocene precipitation balance in the Amazon Basin recorded in deep sea sediments. Quaternary Research 51: 14–26.

23.

Harris

Mix

(2002) Climate and tectonic influences on continental erosion of tropical South America, 0–13 Ma. Geology 30: 447–450.

24.

Harrison

Feinberg

(2008) FORCinel: An improved algorithm for calculating first-order reversal curve distributions using locally weighted regression smoothing. Geochemistry, Geophysics, Geosystems 9: Q05016.

25.

Hong

Lin

et al. (2005) Inverse phase oscillations between the East Asian and Indian Ocean summer monsoons during the last 12000 years and paleo-El Niño. Earth and Planetary Science Letters 231: 337–346.

26.

Hsu

Lin

(2007) Asymmetry of the tripole rainfall pattern during the East Asian summer. Journal of Cliamte 20: 4443–4458.

27.

Hsu

Liu

(2003) Relationship between the Tibetan Plateau heating and East Asian summer monsoon rainfall. Geophysical Research Letters 30: 2066.

28.

Hyland

Sheldon

Van der Voo

et al. (2015) A new paleoprecipitation proxy based on soil magnetic properties: Implications for expanding paleoclimate reconstructions. Bulletin 127: 975–981.

29.

Chen

Balsam

et al. (2004) High resolution hematite/goethite records from Chinese loess sequences for the last glacial-interglacial cycle: Rapid climatic response of the East Asian Monsoon to the tropical Pacific. Geophysical Research Letters 31: L03207.

30.

Jiang

Zhao

Chen

et al. (2017) Decadal climate oscillations during the Little Ice Age of stalagmite record from Heizhugou Cave, Sichuan (in Chinese). Quaternary Sciences 37: 118–129.

31.

Jiang

Liu

Barrón

et al. (2012) Magnetic discrimination between al-substituted hematites synthesized by hydrothermal and thermal dehydration methods and its geological significance. Journal of Geophysical Research Solid Earth 117: B2.

32.

Kämpf

Schwertmann

(1983) Goethite and hematite in a climosequence in southern Brazil and their application in classification of kaolinitic soils. Geoderma 29: 27–39.

33.

Chen

Xiao

et al. (2018) Diatom-based inference of Asian monsoon precipitation from a volcanic lake in southwest China for the last 18.5 ka. Quaternary Science Reviews 182: 109–120.

34.

Liu

Roberts

Larrasoana

et al. (2012) Environmental magnetism: Principles and applications. Reviews of Geophysics 50: RG4002.

35.

Long

Balsam

(2011) Rainfall-dependent transformations of iron oxides in a tropical saprolite transect of Hainan Island, South China: Spectral and magnetic measurements. Journal of Geophysical Research: Earth Surface 116: F03015.

36.

Lyons

Tooth

Duller

(2014) Late Quaternary climatic changes revealed by luminescence dating, mineral magnetism and diffuse reflectance spectroscopy of river terrace palaeosols: A new form of geoproxy data for the southern African interior. Quaternary Science Reviews 95: 43–59.

37.

Masarik

Frank

Schäfer

et al. (2001) Correction of in situ cosmogenic nuclide production rates for geomagnetic field intensity variations during the past 800,000 years. Geochimica Et Cosmochimica Acta 65: 2995–3003.

38.

Mayewski

Meeker

Twickler

et al. (1997) Major features and forcing of high-latitude northern hemisphere atmospheric circulation using a 110,000-year-long glaciochemical series. Journal of Geophysical Research: Oceans 102: 26345–26366.

39.

Peng

Yang

Toney

et al. (2019) Indian Summer Monsoon variations and competing influences between hemispheres since ~35 ka recorded in Tengchongqinghai Lake, southwestern China. Palaeogeography, Palaeoclimatology, Palaeoecology 516: 113–125.

40.

Perry

Hsu

(2000) Geophysical, archaeological, and historical evidence support a solar-output model for climate change. Proceedings of the National Academy of Sciences 97: 12433–12438.

41.

Qian

Lin

(2005) Regional trends in recent precipitation indices in China. Meteorology and Atmospheric Physics 90: 193–207.

42.

Schulz

Mudelsee

(2002) REDFIT: Estimating red-noise spectra directly from unevenly spaced paleoclimatic time series. Computer & Geosciences 28: 421–426.

43.

Schwertmann

(1988) Occurrence and formation of iron oxides in various pedoenvironments. In: Stucki

Goodman

Schwertmann

(eds) Iron in soils and clay minerals. New York: Springer, pp. 267–308.

44.

Schwertmann

Murad

(1983) Effect of pH on the formation of goethite and hematite from ferrihydrite. Clays and Clay Minerals 31: 277–284.

45.

Sheng

et al. (2015) Late-Holocene Indian summer monsoon precipitation history at Lake Lugu, northwestern Yunnan Province, southwestern China. Palaeogeography, Palaeoclimatology, Palaeoecology 438: 24–33.

46.

Sinha

Berkelhammer

Stott

et al. (2011) The leading mode of Indian Summer Monsoon precipitation variability during the last millennium. Geophysical Research Letters 38: 532–560.

47.

Sinha

Cannariato

Stott

et al. (2007) A 900-year (600 to 1500 A.D.) record of the Indian summer monsoon precipitation from the core monsoon zone of India. Geophysical Research Letters 34: 130–144.

48.

Solanki

Usoskin

Kromer

et al. (2004) Unusual activity of the Sun during recent decades compared to the previous 11,000 years. Nature 431: 1084–1087.

49.

Stuiver

Braziunas

(1993) Sun, ocean, climate and atmospheric 14CO2: An evaluation of causal and spectral relationships. The Holocene 3: 289–305.

50.

Tan

Cai

et al. (2011) Climate patterns in north central China during the last 1800 yr and their possible driving force. Climate of the past 7: 685–692.

51.

Tan

Cai

Cheng

et al. (2018) High resolution monsoon precipitation changes on southeastern Tibetan Plateau over the past 2300 years. Quaternary Science Reviews 195: 122–132.

52.

Torrent

Barrón

(2008) Diffuse Reflectance Spectroscopy. In: Ulery

Richard Drees

(eds) Methods of Soil Analysis Part 5—Mineralogical Methods. Madison, WI: Soil Science Society of America.

53.

Viscarra Rossel

Bui

De Caritat

et al. (2010) Mapping iron oxides and the color of Australian soil using visible-near-infrared reflectance spectra. Journal of Geophysical Research: Earth Surface 115: F04031.

54.

Wang

Liu

Cui

et al. (2001a) Terminal Pleistocene/Holocene palaeoenvironmental changes revealed by mineral-magnetism measurements of lake sediments for Dali Nor area, southeastern inner Mongolia Plateau, China. Palaeogeography Palaeoclimatology Palaeoecology 170(1–2): 0–132.

55.

Wang

Gong

Zhu

(2001b) Twentieth-century climatic warming in China in the context of the Holocene. The Holocene 11: 313–321.

56.

Wang

Cheng

Edwards

et al. (2005) The Holocene Asian monsoon: Links to solar changes and North Atlantic climate. Science 308: 854–857.

57.

Wang

Zhu

Pan

et al. (2002) Environmental Characteristics of An Acid Qinghai Lake in Tengchong, Yunnan Province (in Chinese). Journal of Lake Sciences 14: 117–124.

58.

Xiao

Shen

Haberle

et al. (2015) Vegetation, fire, and climate history during the last 18500 cal a BP in south-western Yunnan Province, China. Journal of Quaternary Science 30: 859–869.

59.

Sheng

Lan

et al. (2014) Decadal/multi-decadal temperature discrepancies along the eastern margin of the Tibetan Plateau. Quaternary Science Reviews 89: 85–93.

60.

Zhou

Lan

et al. (2015) Late-Holocene Indian summer monsoon variations recorded at Lake Erhai, Southwestern China. Quaternary Research 83: 307–314.

61.

Yang

Braeuning

Johnson

et al. (2002) General characteristics of temperature variation in China during the last two millennia. Geophysical Research Letters 29: 38–31.

62.

Yang

Chen

Huang

et al. (2016) δ¹⁸O record of a 700-years-old speleothem from the Shuiyuan Cave in eastern Nanling Mountain and its paleoclimatic implications (in Chinese). Geochimica 45: 164–172.

63.

Yapp

(2001) Rusty relics of earth history: Iron (III) oxides, isotopes, and surficial environments. Annual Review of Earth and Planetary Sciences 29: 165–199.

64.

Zeng

Chen

Zhu

et al. (2012) The wet Little Ice Age recorded by sediments in Huguangyan Lake, tropical south China. Quaternary International 263: 55–62.

65.

Zhang

Tang

Chen

(2017) Recent changes in the moisture source of precipitation over the Tibetan Plateau. Journal of Climate 30: 1807–1819.

66.

Zhang

Sun

et al. (2015) Late Quaternary carbon cycling responses to environmental change revealed by multi-proxy analyses of a sediment core from an upland lake in southwest China. Quaternary Research 84: 415–422.

67.

Zhang

Griffiths

Chiang

JCH

et al. (2018) East Asian hydroclimate modulated by the position of the westerlies during Termination I. Science 362: 580–583.

68.

Zhang

Cheng

Edwards

et al. (2008) A test of climate, sun, and culture relationships from an 1810-year Chinese cave record. Science 322: 940–942.

69.

Zhang

Balsam

et al. (2007) High resolution hematite and goethite records from ODP 1143, South China Sea: Co-evolution of monsoonal precipitation and El Niño over the past 600,000years. Earth and Planetary Science Letters 264: 136–150.

70.

Zheng

Hao

Zhang

et al. (2014) Drought/flood spatial patterns in centennial cold and warm periods of the past 2000 years over eastern China (in Chinese). Chinese Science Bulletin (Chin Ver) 59: 2964–2971.

71.

Zhou

Zhao

Liu

et al. (2011) Characteristics of decadal-centennial-scale changes in East Asian summer monsoon circulation and precipitation during the Medieval Warm Period and Little Ice Age and in the present day. Chinese Science Bulletin 56: 3003.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.06 MB