Unprecedented Warming Revealed from Multi-proxy Reconstruction of Temperature in Southern China for the Past 160 Years

Using the southern limit of snowfall recorded in Chinese documents, chronologies of tree-ring width, and tree-ring stable oxygen isotope（δ^（18）O）, the annual temperature anomaly in southern China during 1850–2009 is reconstructed using the method of signal decomposition and synthesis. The results show that the linear trend was 0.47℃（100 yr）^（-1）over 1871–2009,and the two most rapid warming intervals occurred in 1877–1938 and 1968–2007, at rates of 0.125℃（10 yr）^（-1）and 0.258℃（10 yr）^（-1）, respectively. The decadal variation shows that the temperature in the moderate warm interval of the 1910s–1930s was notably lower than that of the 1980s–2000s, which suggests that the warming since the 1980s was unprecedented for the past 160 years, though a warming hiatus existed in the 2000s. Additionally, there was a rapid cooling starting from the 1860s,followed by a cold interval until the early 1890s, with the coldest years in 1892 and 1893. A slight temperature decline was also found from the 1940s to the late 1960s. This study provides an independent case to validate the global warming for the past 160 years and its hiatus recently, because the proxy data are not affected by urbanization.

Evaluation of ERA-Interim Monthly Temperature Data over the Tibetan Plateau

In this study, surface air temperature from 75 meteorological stations above 3000 m on the Tibetan Plateau are applied for evaluation of the European Centre for Medium-Range Weather Forecasts(ECMWF) third-generation reanalysis product ERA-Interim in the period of 1979-2010. High correlations ranging from 0.973 to 0.999 indicate that ERA-Interim could capture the annual cycle very well. However, an average root-meansquare error(rmse) of 3.7°C for all stations reveals that ERA-Interim could not be applied directly for the individual sites. The biases can be mainly attributed to the altitude differences between ERA-Interim grid points and stations. An elevation correction method based on monthly lapse rates is limited to reduce the bias for all stations. Generally, ERA-Interim captured the Plateau-Wide annual and seasonal climatologies very well. The spatial variance is highly related to the topographic features of the TP. The temperature increases significantly(10°C- 15°C) from the western to the eastern Tibetan Plateau for all seasons, in particular during winter and summer. A significant warming trend(0.49°C/decade) is found over the entire Tibetan Plateau using station time series from 1979-2010. ERA-Interim captures the annual warming trend with an increase rate of 0.33°C /decade very well. The observation data and ERA-Interim data both showed the largest warming trends in winter with values of 0.67°C/decade and 0.41°C/decade, respectively. We conclude that in general ERA-Interim captures the temperature trends very well and ERA-Interim is reliable for climate change investigation over the Tibetan Plateau under the premise of cautious interpretation.

INCONSECUTIVE “SANDWICH STRUCTURE” PATTERN FOR HIGH TEMPERATURE WARM WATER IN THE WESTERN PACIFIC WARM POOL

An inconsecutive high frequency distribution with a"sandwich structure"pattern for high temperature warm water warmer than 29℃ in the western Pacific warm pool(WPWP) was found using Tropical Rainfall Measuring Mission(TRMM) sea surface temperature(SST) data,a relatively high resolution data for space.This phenomenon only shows up in boreal summer(June to September),and becomes obvious when WPWP SST is higher than 29℃.As observed,East Asian summer monsoon(EASM) impinges on Philippine Islands in July,which has an important impact on the formation and maintenance of the "sandwich structure".Winds affect the distribution of SST in two ways:one by increasing the local latent heat flux and the other by transporting cold water towards the southeast of Philippine Islands.

Evolution of Surface Sensible Heat over the Tibetan Plateau Under the Recent Global Warming Hiatus

Based on regular surface meteorological observations and NCEP/DOE reanalysis data, this study investigates the evolution of surface sensible heat（SH） over the central and eastern Tibetan Plateau（CE-TP） under the recent global warming hiatus. The results reveal that the SH over the CE-TP presents a recovery since the slowdown of the global warming. The restored surface wind speed together with increased difference in ground-air temperature contribute to the recovery in SH.During the global warming hiatus, the persistent weakening wind speed is alleviated due to the variation of the meridional temperature gradient. Meanwhile, the ground surface temperature and the difference in ground-air temperature show a significant increasing trend in that period caused by the increased total cloud amount, especially at night. At nighttime, the increased total cloud cover reduces the surface effective radiation via a strengthening of atmospheric counter radiation and subsequently brings about a clear upward trend in ground surface temperature and the difference in ground-air temperature.Cloud–radiation feedback plays a significant role in the evolution of the surface temperature and even SH during the global warming hiatus. Consequently, besides the surface wind speed, the difference in ground-air temperature becomes another significant factor for the variation in SH since the slowdown of global warming, particularly at night.

Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods

This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃（100 yr）^（-1）; however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern： dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.

Distribution Pattern of Vascular Plant Species of Mountains in Nepal and their Fate Against Global Warming

This study aims to find the altitudinal distribution pattern of vascular plant species reported from high mountain of Nepal(Manang) along the whole Himalayan elevation gradient, and evaluate their fate against climate change. Data was gathered from multiple sources, field investigations, literatures, and herbarium specimens. Altogether, 303 vascular plant species were reported from Manang. We used a published data to calculate distribution range of each species by interpolating between its upper and lower elevation limits. The relationship between elevation and species richness is elucidated by generalized linear model. The consequence of global warming upon Manang's vascular plant species was estimated based on projected temperature change for next century and adiabatic lapse rate along the elevation gradient of the Himalayas. The vascular plant species richness has a unimodel relationship with elevation along the whole elevation gradient of Nepal as well as in three biogeographical regions of Nepal. Vascular plants of Manang are found distributed from low land Terai to high alpine regions of Nepal and their elevation distribution range varies from 200 to 4700 m. Out of 303 vascular plants of Manang, only seven species might be affected if temperature increase by 1.5°C, whereas at least 70 species will be affected with 5°C temperature increased. However, the majority of species(233 species) have wider distribution range(> 1000 m) and more than 5°C temperature tolerance range, thus they are likely to be less affected from global warming by the end of 21 st century.

Key parameters for low temperature warm compaction of high density iron-based P/M materials

In order to reduce powder temperature to lower than 100℃ in warm compaction by changing polymer lubricant design, powder flowability, warm compacting behavior, lubricating mode as well as ultimate tensile strength after sinter-hardening and tempering were investigated systematically. By means of low temperature warm pressing and sintered hardening technique, samples with the sintered densities of 7.407.45g/cm3 and the strengths of 950 1390MPa are achieved as the early compacting pressure is 686735MPa.

Role of ocean upper layer warm water in the rapid intensification of tropical cyclones: A case study of typhoon Rammasun(1409)

Rammasun intensified rapidly from tropical storm to super typhoon in the northern South China Sea（NSCS）before its landfall on Hainan Island. Analysis of observed data shows that the anomalous ocean upper layer warm water（WW） is important to the rapid intensification of Rammasun. During the period of Rammasun, sea surface temperature（SST） in the NSCS was much warmer than the climatological SST. The anomalous WW supplied more energy to Rammasun, resulting in its rapid intensification. Numerical simulations further confirm that the NSCS WW plays an important role in the rapid intensification of Rammasun. As the WW is removed, the intensification of Rammasun is only 25 h Pa, which is 58.1% of that in the original SST-forced run.

Multiple ocean surface temperature changes induced multi-decadal global warming rate

Subject Code:D05Under support of the National Natural Science Foundation of China,a concerted study by Dr.Huang Gang(黄刚)from the Institute of Atmospheric Physics,Chinese Academy of Sciences,climate scientist Jing-Jia Luo from the Australian Bureau of Meteorology,Dr.Yao Shuailei(姚帅磊)from the Institute

Distinctive South and East Asian monsoon circulation responses to global warming

The Asian summer monsoon(ASM)is the most energetic circulation system.Projecting its future change is critical for the mitigation and adaptation of billions of people living in the region.There are two important components within the ASM:South Asian summer monsoon(SASM)and East Asian summer monsoon(EASM).Although current state-of-the-art climate models projected increased precipitation in both SASM and EASM due to the increase of atmospheric moisture,their circulation changes differ markedlyÐA robust strengthening(weakening)of EASM(SASM)circulation was projected.By separating fast and slow processes in response to increased CO_(2) radiative forcing,we demonstrate that EASM circulation strengthening is attributed to the fast land warming and associated Tibetan Plateau thermal forcing.In contrast,SASM circulation weakening is primarily attributed to an El Niño-like oceanic warming pattern in the tropical Pacific and associated suppressed precipitation over the Maritime Continent.

Mutation of DELAYED GREENING1 impairs chloroplast RNA editing at elevated ambient temperature in Arabidopsis

Chloroplasts are important for plant growth and development.RNA editing in chloroplast converts cytidines(Cs)to uridine s(Us)at specific transcript positions and provides a correction mechanism to restore conserved codons or creates start or stop codons.However,the underlined molecular mechanism is not yet fully unders tood.In the present study,we identi fied a thermo-sensi tive mutantin leaf color 1(tst1)and found that TSL1 is allelic to DELAYED GREENING 1(DG1).The mis sense mutation of DG1 in tsl1 mutant confers a high temperature sensitivity and impaired chloroplast development at an elevated ambient temperature in Arabidopsis.Subsequent analysis showed that chloroplast RNA editing at seve ral sites including accD-2568,ndhD-2,and petL-5 is impaired in tsl1 mutant plants grown at an elevated temperature.DG1 interacts with MORF2 and other proteins such as DYW1 and DYW2 involved in chloroplast RNA editing.In vitro RNA electrophoretic mobility shift assay demonstrated that DG1 binds to RNA targets such as accD,ndhD,and petL.Thus,our results revealed that DG1 is important for maintaining chloroplast mRNA editing in Arabidopsis.

Effects of Temperature and Moisture on Soil Organic Matter Decomposition Along Elevation Gradients on the Changbai Mountains, Northeast China

Decomposition of soil organic matter(SOM) is of importance for CO_2 exchange between soil and atmosphere and soil temperature and moisture are considered as two important factors controlling SOM decomposition. In this study, soil samples were collected at 5 elevations ranging from 753 to 2 357 m on the Changbai Mountains in Northeast China, and incubated under different temperatures(5, 10, 15, 20, 25, and 30?C) and soil moisture levels(30%, 60%, and 90% of saturated soil moisture) to investigate the effects of both on SOM decomposition and its temperature sensitivity at different elevations. The results showed that incubation temperature(F = 1 425.10, P < 0.001), soil moisture(F = 1 327.65, P < 0.001), and elevation(F = 1 937.54, P < 0.001) all had significant influences on the decomposition rate of SOM. The significant effect of the interaction of incubation temperature and soil moisture on the SOM decomposition rate was observed at all the 5 sampling elevations(P < 0.001). A two-factor model that used temperature and moisture as variables fitted the SOM decomposition rate well(P < 0.001) and could explain 80%–93% of the variation of SOM decomposition rate at the 5 elevations. Temperature sensitivity of SOM decomposition, expressed as the change of SOM decomposition rate in response to a 10?C increase in temperature(Q_(10)), was significantly different among the different elevations(P < 0.01), but no apparent trend with elevation was discernible. In addition, soil moisture and incubation temperature both had great impacts on the Q_(10) value(P < 0.01), which increased significantly with increasing soil moisture or incubation temperature. Furthermore, the SOM decomposition rate was significantly related to soil total Gram-positive bacteria(R^2= 0.33, P < 0.01) and total Gram-negative bacteria(R^2= 0.58, P < 0.001). These findings highlight the importance of soil moisture to SOM decomposition and its Q_(10) value,which needs to be emphasized under warming climate scenarios.

REVEILLE 7 inhibits the expression of the circadian clock gene EARLY FLOWERING 4 to fine-tune hypocotyl growth in response to warm temperatures

The circadian clock maintains the daily rhythms of plant growth and anticipates predictable ambient temperature cycles.The evening complex(EC),comprising EARLY FLOWERING 3(ELF3),ELF4,and LUX ARRHYTHMO,plays an essential role in suppressing thermoresponsive hypocotyl growth by negatively regulating PHYTOCHROME INTERACTING FACTOR 4(PIF4)activity and its downstream targets in Arabidopsis thaliana.However,how EC activity is attenuated by warm temperatures remains unclear.Here,we demonstrate that warm temperature-induced REVEILLE7(RVE7)fine-tunes thermoresponsive growth in Arabidopsis by repressing ELF4 expression.RVE7 transcript and RVE7 protein levels increased in response to warm temperatures.Under warm temperature conditions,an rve7 loss-of-function mutant had shorter hypocotyls,while overexpressing RVE7 promoted hypocotyl elongation.PIF4 accumulation and downstream transcriptional effects were reduced in the rve7 mutant but enhanced in RVE7 overexpression plants under warm conditions.RVE7 associates with the Evening Element in the ELF4 promoter and directly represses its transcription.ELF4 is epistatic to RVE7,and overexpressing ELF4 suppressed the phenotype of the RVE7 overexpression line under warm temperature conditions.Together,our results identify RVE7 as an important regulator of thermoresponsive growth that functions(in part)by controlling ELF4 transcription,highlighting the importance of ELF4 for thermomorphogenesis in plants.

Impact of 1.5°C and 2.0°C global warming on aircraft takeoff performance in China

Associated with global warming, climate extremes such as extreme temperature will significantly increase. Understanding how climate change will impact the airflights is important to the planning of future flight operations. In this study, the impacts of 1.5 and 2 degree's global warming on the aircraft takeoff performance in China are investigated using a unique climate projection data from an international collaboration project named HAPPI. It is found that the mean summer daily maximum temperature, which is a major factor that affects the flight through changing the aircraft's takeoff weight, will increase significantly with magnitude less than 1.5℃ over most parts of China except for the Tibetan Plateau. The half a degree additional global warming will lead to higher extreme temperature in the arid and semi-arid western China, the Tibetan Plateau and the northeastern China, while the change in eastern China is weak. Five airports including Beijing, Shanghai, Kunming, Lasa and Urumqi will see ～1.0°-2.0℃(1.4°-3.0℃) higher daily maximum temperature under 1.5℃(2.0℃) scenario. The half-degree additional warming will lead to a shift toward higher extreme temperature in these five sites. For both1.5° and 2.0℃ scenarios, the number of weight-restriction days will increase significantly at 3 airports including Beijing, Shanghai, and Lasa. Urumqi will witness an increase of weight-restriction days only in 2.0℃ future.

PIFs‑and COP1‑HY5‑mediated temperature signaling in higher plants

Plants have to cope with the surrounding changing environmental stimuli to optimize their physiological and devel-opmental response throughout their entire life cycle.Light and temperature are two critical environmental cues that fluctuate greatly during day-night cycles and seasonal changes.These two external signals coordinately control the plant growth and development.Distinct spectrum of light signals are perceived by a group of wavelength-specific photoreceptors in plants.PIFs and COP1-HY5 are two predominant signaling hubs that control the expression of a large number of light-responsive genes and subsequent light-mediated development in plants.In parallel,plants also transmit low or warm temperature signals to these two regulatory modules that precisely modulate the responsive-ness of low or warm temperatures.The core component of circadian clock ELF3 integrates signals from light and warm temperatures to regulate physiological and developmental processes in plants.In this review,we summarize and discuss recent advances and progresses on PIFs-,COP1-HY5-and ELF3-mediated light,low or warm temperature signaling,and highlight emerging insights regarding the interactions between light and low or warm temperature signal transduction pathways in the control of plant growth.

Combined effects of elevated temperature and CO_2 concentration on Cd and Zn accumulation dynamics in Triticum aestivum L.

A simulated climate warming experiment was conducted to evaluate the combined effects of elevated temperature and CO_2 concentration on the bioaccumulation,translocation and subcellular distributions of Cd and Zn in wheat seedlings（Triticum aestivum L.cv.Xihan 1.） at Dingxi,Gansu Province,China.The objective was to find evidence that global climate change is affecting the bioaccumulation of Cd and Zn in T.aestivum L.cv.Xihan 1.The results showed that compared to control A,elevated temperature and CO_2 increased Cd bioaccumulation in the shoots by 1.4–2.5 times,and increased that in the roots by 1.2–1.5times,but decreased Zn levels in wheat shoots by 1.4–2.0 times,while decreased that in the roots by 1.6–1.9 times.Moreover,temperature and CO_2 concentration increase also led to increased Cd concentration,and decreased Zn concentration in subcellular compartments of wheat seedlings.The largest Cd concentration increase（174.4%） was observed in the cell wall and debris fractions of shoots after they were subjected to the highest CO_2 and temperature treatment（TC3）.The largest Zn concentration decrease（53.1%） was observed in the soluble（F3） fractions of shoots after they were subjected to the medium CO_2 and temperature treatment（TC2）.The temperature and CO_2 increase had no significant effect on the proportional distribution of Cd and Zn in the subcellular fractions.The root-to-shoot translocation of Cd increased with the increasing temperature and CO_2 concentration.However,the Zn distributions only fluctuated within a small range.

General characteristics of climate changes during the past 2000 years in China

The general characteristics of climate changes over the past 2000 years in China,regional differences and uncertainties were analyzed based on the recently peer-reviewed high time-resolution climatic reconstructions.The results showed that there exists four warm periods of the temperature variation in China since the Qin Dynasty,including the western and eastern Han Dynasties(200 BC-AD 180),the Sui and Tang dynasties(541-810),the Song and Yuan dynasties(931-1320),and the 20th century,and three cold phases involving the Wei,Jin,and North-South Dynasties(181-540),the late Tang Dynasty(811-930),and the Ming and Qing dynasties(1321-1920).The Song and Yuan warm period is consistent with the Medieval Warm Period over the Northern Hemisphere,and the cold phases of the North-South Dynasties and the Ming and Qing dynasties are paralleled to the Dark Ages Cold Period and the Little Ice Age,respectively.The 13th-15th century could be a shift to the wet condition of the climate,and the low precipitation variability is exhibited in western China prior to 1500.In the context of the climate warming,the pattern of the drought in north and flood in south is prevalent over the eastern China.In addition,the published reconstructions have a high level of confidence for the past 500 years,but large uncertainties exist prior to the 16th century.