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1.
《地理学报(英文版)》2019,(1)
This paper reports the phenological response of forest vegetation to climate change(changes in temperature and precipitation) based on Moderate Resolution Imaging Spectroradiometer(MODIS) Enhanced Vegetation Index(EVI) time-series images from 2000 to 2015. The phenological parameters of forest vegetation in the Funiu Mountains during this period were determined from the temperature and precipitation data using the Savitzky–Golay filter method, dynamic threshold method, Mann-Kendall trend test, the Theil-Sen estimator, ANUSPLIN interpolation and correlation analyses. The results are summarized as follows:(1) The start of the growing season(SOS) of the forest vegetation mainly concentrated in day of year(DOY) 105–120, the end of the growing season(EOS) concentrated in DOY 285–315, and the growing season length(GSL) ranged between 165 and 195 days. There is an evident correlation between forest phenology and altitude. With increasing altitude, the SOS, EOS and GSL presented a significant delayed, advanced and shortening trend, respectively.(2) Both SOS and EOS of the forest vegetation displayed the delayed trend, the delayed pixels accounted for 76.57% and 83.81% of the total, respectively. The GSL of the forest vegetation was lengthened, and the lengthened pixels accounted for 61.21% of the total. The change in GSL was mainly caused by the decrease in spring temperature in the region.(3) The SOS of the forest vegetation was significantly partially correlated with the monthly average temperature in March, with most correlations being negative; that is, the delay in SOS was mainly attributed to the temperature decrease in March. The EOS was significantly partially correlated with precipitation in September, with most correlations being positive; that is, the EOS was clearly delayed with increasing precipitation in September. The GSL of the forest vegetation was influenced by both temperature and precipitation throughout the growing season. For most regions, GSL was most closely related to the monthly average temperature and precipitation in August. 相似文献
2.
《地理学报(英文版)》2017,(9)
In this study, the spatial distribution and changing trends of agricultural heat and precipitation resources in Northeast China were analyzed to explore the impacts of future climate changes on agroclimatic resources in the region. This research is based on the output meteorological data from the regional climate model system for Northeast China from 2005 to 2099, under low and high radiative forcing scenarios RCP4.5(low emission scenario) and RCP8.5(high emission scenario) as proposed in IPCC AR5. Model outputs under the baseline scenario, and RCP4.5 and RCP8.5 scenarios were assimilated with observed data from 91 meteorological stations in Northeast China from 1961 to 2010 to perform the analyses. The results indicate that:(1) The spatial distribution of temperature decreases from south to north, and the temperature is projected to increase in all regions, especially under a high emission scenario. The average annual temperature under the baseline scenario is 7.70°C, and the average annual temperatures under RCP4.5 and RCP8.5 are 9.67°C and 10.66°C, respectively. Other agricultural heat resources change in accordance with temperature changes. Specifically, the first day with temperatures ≥10°C arrives 3 to 4 d earlier, the first frost date is delayed by 2 to 6 d, and the duration of the growing season is lengthened by 4 to 10 d, and the accumulated temperature increases by 400 to 700°C·d. Water resources exhibit slight but not significant increases.(2) While the historical temperature increase rate is 0.35°C/10 a, the rate of future temperature increase is the highest under the RCP8.5 scenario at 0.48°C/10 a, compared to 0.19°C/10 a under the RCP4.5 scenario. In the later part of this century, the trend of temperature increase is significantly faster under the RCP8.5 scenario than under the RCP4.5 scenario, with faster increases in the northern region. Other agricultural heat resources exhibit similar trends as temperature, but with different specific spatial distributions. Precipitation in the growing season generally shows an increasing but insignificant trend in the future, with relatively large yearly fluctuations. Precipitation in the eastern region is projected to increase, while a decrease is expected in the western region. The future climate in Northeast China will change towards higher temperature and humidity. The heat resource will increase globally, however its disparity with the change in precipitation may negatively affect agricultural activities. 相似文献
3.
过去300年大兴安岭北部气候变化特征（英文） 总被引：1，自引：0，他引：1
The Greater Khingan Mountains(Daxinganling) are China's important ecological protective screen and also the region most sensitive to climate changes. To gain an in-depth understanding and reveal the climate change characteristic in this high-latitude, cold and data-insufficient region is of great importance to maintaining ecological safety and corresponding to global climate changes. In this article, the annual average temperature, precipitation and sunshine duration series were firstly constructed using tree-ring data and the meteorological observation data. Then, using the climate tendency rate method, moving-t-testing method, Yamamoto method and wavelet analysis method, we have investigated the climate changes in the region during the past 307 years. Results indicate that, since 1707, the annual average temperature increased significantly, the precipitation increased slightly and the sunshine duration decreased, with the tendency rates of 0.06℃/10 a, 0.79 mm/10 a and –5.15 h/10 a, respectively(P≤0.01). Since the 21 st century, the period with the greatest increase of the annual average temperature(also with the greatest increase of precipitation) corresponds to the period with greatest decrease of sunshine duration. Three sudden changes of the annual average temperature and sunshine duration occurred in this period while two sudden changes of precipitation occurred. The strong sudden-change years of precipitation and sunshine duration are basically consistent with the sudden-change years of annual average temperature, suggesting that in the mid-1860 s, the climatic sudden change or transition really existed in this region. In the time domain, the climatic series of this region exhibit obvious local variation characteristics. The annual average temperature and sunshine duration exhibit the periodic variations of 25 years while the precipitation exhibits a periodic variation of 20 years. Based on these periodic characteristics, one can infer that in the period from 2013 to 2030, the temperature will be at a high-temperature stage, the precipitation will be at an abundant-precipitation stage and the sunshine duration will be at an less-sunshine stage. In terms of spatial distribution, the leading distribution type of the annual average temperature in this region shows integrity, i.e., it is easily higher or lower in the whole region; and the second distribution type is more(or less) in the southwest parts and less(or more) in the northeast parts. Precipitation and sunshine duration exhibit complex spatial distribution and include fourspatial distribution types. The present study can provide scientific basis for the security investigation of homeland, ecological and water resources as well as economic development programming in China's northern borders. 相似文献
4.
Based on TIMESAT 3.2 platform, MODIS NDVI data(2000–2015) of Qaidam Basin are fitted, and three main phenological parameters are extracted with the method of dynamic threshold, including the start of growth season(SGS), the end of growth season(EGS) and the length of growth season(LGS). The spatial and temporal variation of vegetation phenology and its response to climate changes are analyzed respectively. The conclusions are as follows:(1) SGS is mainly delayed as a whole. Areas delayed are more than the advanced in EGS, and EGS is a little delayed as a whole. LGS is generally shortened.(2) With the altitude rising, SGS is delayed, EGS is advanced, and LGS is shortened and phenophase appears a big variation below 3000 m and above 5000 m.(3) From 2000 to 2015, the temperature appears a slight increase along with a big fluctuation, and the precipitation increases evidently.(4) Response of phenophase to precipitation is not obvious in the low elevation humid regions, where SGS arrives early and EGS delays; while, in the upper part of the mountain regions, SGS delays and EGS advances with temperature rising, SGS arrives early and EGS delays with precipitation increasing. 相似文献
5.
Fencing is the most common land-management practice to protect grassland degradation from livestock overgrazing on the Tibetan Plateau. However, it is unclear whether fencing reduces CO_2, CH_4, and N_2O emission. Here, we selected four vegetation types of alpine meadow(graminoid, shrub, forb, and sparse vegetation) to determine fencing effects on ecosystem respiration(Re), CH_4, and N_2O fluxes during the growing season. Despite increased average monthly ecosystem respiration(Re) for fenced graminoid vegetation at the end of the growing season, there was no significant difference between grazing and fencing across all vegetation types. Fencing significantly reduced average CH_4 uptake by about 50% in 2008 only for forb vegetation and increased average N_2O release for graminoid vegetation by 38% and 48% in 2008 and 2009,respectively. Temperature, moisture, total organic carbon, C/N, nitrate, ammonia, and/or bulk density of soil, as well as above-and belowground biomass, explained 19%~71% and 6%~33% of variation in daily and average Re and CH_4 fluxes across all vegetation types, while soil-bulk density explained 27% of variation in average N_2O fluxes. Stepwise regression showed that soil temperature and soil moisture controlled average Re, while soil moisture and bulk density controlled average CH_4 fluxes. These results indicate that abiotic factors control Re, CH_4, and N_2O fluxes; and grazing exclusion has little effect on reducing their emission—implying that climatic change rather than grazing may have a more important influence on the budgets of Re and CH_4 for the Tibetan alpine meadow during the growing season. 相似文献
6.
经验模态分解下中国气温变化趋势的区域特征 总被引：3，自引：1，他引：2
By the Empirical Mode Decomposition method, we analyzed the observed monthly average temperature in more than 700 stations from 1951-2001 over China. Simultaneously, the temperature variability of each station is calculated by this method, and classification chart of long term trend and temperature variability distributing chart of China are obtained, supported by GIS, 1 kmxl km resolution. The results show that： in recent 50 years, the temperature has increased by more than 0.4~C/10a in most parts of northern China, while in Southwest China and the middle and lower Yangtze Valley, the increase is not significant. The areas with a negative temperature change rate are distributed sporadically in Southwest China. Meanwhile, the temperature data from 1881 to 2001 in nine study regions in China are also analyzed, indicating that in the past 100 years, the temperature has been increasing all the way in Northeast China, North China, South China, Northwest China and Xinjiang and declining in Southwest China. An inverse ‘V-shaped’ trend is also found in Central China. But in Tibet the change is less significant. 相似文献
7.
According to the textual research into the historical documents dominated by archives yearly, as well as the verification with several other kinds of data, the later or earlier starting time of the rainy seasons in Yunnan during 1711-1982 has been reconstructed. The analysis indicates that there are obvious fluctuations in the starting date of the rainy seasons in Yunnan in a year or years, and long fluctuation on the decadal scale. The rainy season comes earlier in the early 18th century, later in the 19th century and earlier again in the 20th century. This reflects to a certain degree the gradual change of the summer monsoon in Yunnan. There exists an obvious quasi-3 years cycle, which is related to EI-Nino＇s quasi-3 years cycle, and a 11.3-year cycle which is notably related to the 11-year cycle of the solar activity of starting date of the rainy seasons in Yunnan. Meanwhile, the dissertation finds that the EI-Nino is very important to the starting date of the rainy seasons in Yunnan. The starting date of the rainy seasons in Yunnan often comes later or normally in the year of EI-Nino. However, there is an obvious imperfect period in such influence, which in turn may mean that there is a certain fluctuation in the effect of ENSO on Asian summer monsoon. 相似文献
8.
YUXinfang ZHUANGDafang HOUXiyong CHENHua 《地理学报(英文版)》2005,15(2):239-246
The role of remote sensing in phenological studies is increasingly regarded as a key to understand large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for forest phenological patterns. The forest phenological phase of Northeast China (NE China) and its spatial characteristics were inferred using 1-km 10-day MODIS normalized difference vegetation index (NDVI) datasets of 2002. The threshold-based method was used to estimate three key forest phenological variables, which are the start of growing season (SOS), the end of growing season (EOS) and growing season length (GSL).Then the spatial patterns of forest phenological variables of NE China were mapped and analyzed. The derived phenological variables were validated by the field observed data from published papers in the same study area. Results indicate that forest phenological phase from MODIS data is comparable with the observed data. As the derived forest phenological pattern is related to forest type distribution, it is helpful to discriminate between forest types. 相似文献
9.
《地理学报(英文版)》2019,(1)
Lake ice phenology is considered a sensitive indicator of regional climate change. We utilized time series information of this kind extracted from a series of multi-source remote sensing(RS) datasets including the MOD09 GQ surface reflectance product, Landsat TM/ETM_+ images, and meteorological records to analyze spatiotemporal variations of ice phenology of Qinghai Lake between 2000 and 2016 applying both RS and GIS technology. We also identified the climatic factors that have influenced lake ice phenology over time and draw a number of conclusions. First, data show that freeze-up start(FUS), freeze-up end(FUE), break-up start(BUS), and break-up end(BUE) on Qinghai Lake usually occurred in mid-December, early January, mid-to-late March, and early April, respectively. The average freezing duration(FD, between FUE and BUE), complete freezing duration(CFD, between FUE and BUS), ice coverage duration(ICD, between FUS and BUE), and ablation duration(AD, between BUS and BUE) were 88 days, 77 days, 108 days and 10 days, respectively. Second, while the results of this analysis reveal considerable differences in ice phenology on Qinghai Lake between 2000 and 2016, there has been relatively little variation in FUS times. Data show that FUE dates had also tended to fluctuate over time, initially advancing and then being delayed, while the opposite was the case for BUS dates as these advanced between 2012 and 2016. Overall, there was a shortening trend of Qinghai Lake's FD in two periods, 2000–2005 and 2010–2016, which was shorter than those seen on other lakes within the hinterland of the Tibetan Plateau. Third, Qinghai Lake can be characterized by similar spatial patterns in both freeze-up(FU) and break-up(BU) processes, as parts of the surface which freeze earlier also start to melt first, distinctly different from some other lakes on the Tibetan Plateau. A further feature of Qinghai Lake ice phenology is that FU duration(between 18 days and 31 days) is about 10 days longer than BU duration(between 7 days and 20 days). Fourth, data show that negative temperature accumulated during the winter half year(between October and the following April) also plays a dominant role in ice phenology variations of Qinghai Lake. Precipitation and wind speed both also exert direct influences on the formation and melting of lake ice cover and also cannot be neglected. 相似文献
10.
By the Empirical Mode Decomposition method, we analyzed the observed monthly average temperature in more than 700 stations from 1951–2001 over China. Simultaneously, the temperature variability of each station is calculated by this method, and classification chart of long term trend and temperature variability distributing chart of China are obtained, supported by GIS, 1 km×1 km resolution. The results show that: in recent 50 years, the temperature has increased by more than 0.4℃/10a in most parts of northern China, while in Southwest China and the middle and lower Yangtze Valley, the increase is not significant. The areas with a negative temperature change rate are distributed sporadically in Southwest China. Meanwhile, the temperature data from 1881 to 2001 in nine study regions in China are also analyzed, indicating that in the past 100 years, the temperature has been increasing all the way in Northeast China, North China, South China, Northwest China and Xinjiang and declining in Southwest China. An inverse ‘V-shaped’ trend is also found in Central China. But in Tibet the change is less significant. 相似文献
11.
《地理学报(英文版)》2017,(7)
Though many studies have focused on the causes of shifts in trend of temperature, whether the response of vegetation growth to temperature has changed is still not very clear. In this study, we analyzed the spatial features of the trend changes of temperature during the growing season and the response of vegetation growth in China based on observed climatic data and the normalized difference vegetation index(NDVI) from 1984 to 2011. An obvious warming to cooling shift during growing season from the period 1984–1997 to the period 1998–2011 was identified in the northern and northeastern regions of China, whereas a totally converse shift was observed in the southern and western regions, suggesting large spatial heterogeneity of changes of the trend of growing season temperature throughout China. China as a whole, a significant positive relationship between vegetation growth and temperature during 1984 to 1997 has been greatly weakened during 1998–2011. This change of response of vegetation growth to temperature has also been confirmed by Granger causality test. On regional scales, obvious shifts in relationship between vegetation growth and temperature were identified in temperate desert region and rainforest region. Furthermore, by comprehensively analyzing of the relationship between NDVI and climate variables, an overall reduction of impacts of climate factors on vegetation growth was identified over China during recent years, indicating enhanced influences from human associated activities. 相似文献
12.
《地理学报(英文版)》2017,(9)
With the global warming, crop phenological shifts in responses to climate change have become a hot research topic. Based on the long-term observed agro-meteorological phenological data(1981–2009) and meteorological data, we quantitatively analyzed temporal and spatial shifts in maize phenology and their sensitivities to key climate factors change using climate tendency rate and sensitivity analysis methods. Results indicated that the sowing date was significantly delayed and the delay tendency rate was 9.0 d·10a-1. But the stages from emergence to maturity occurred earlier(0.1 d·10a-1θ1.7 d·10a-1, θ is the change slope of maize phenology). The length of vegetative period(VPL)(from emergence to tasseling) was shortened by 0.9 d·10a-1, while the length of generative period(GPL)(from tasseling to maturity) was lengthened by 1.7 d·10a-1. The growing season length(GSL)(from emergence to maturity) was lengthened by 0.4 d·10a-1. Correlation analysis indicated that maize phenology was significantly correlated with average temperature, precipitation, sunshine duration and growing degree days(GDD)(p0.01). Average temperature had significant negative correlation relationship, while precipitation, sunshine duration and growing degree days had significant positive correlations with maize phenology. Sensitivity analysis indicated that maize phenology showed different responses to variations in key climate factors, especially at different sites. The conclusions of this research could provide scientific supports for agricultural adaptation to climate change to address the global food security issue. 相似文献
13.
14.
WenWen Wang 《寒旱区科学》2013,5(2):0240-0250
Based on daily maximum and minimum surface air temperature and precipitation records at 48 meteorological stations in Xinjiang, the spatial and temporal distributions of climate extreme indices have been analyzed during 1961-2008. Twelve temperature extreme indices and six precipitation extreme indices are studied. Temperature extremes are highly correlated to annual mean temperature, which appears to be significantly increasing by 0.08 °C per year, indicating that changes in temperature extremes reflect consistent warming. The warming tendency is clearer at stations in northern Xinjiang as reflected by mean temperature. The frequencies of cold days and nights have both decreased, respectively by 0.86 and 2.45 d/decade, but the frequencies of warm days and nights have both increased, respectively by +1.62 and +4.85 d/decade. Over the same period, the number of frost days shows a statistically significant decreasing trend of 2.54 d/decade. The growing season length and the number of summer days exhibit significant increasing trends at rates of +2.62 and +2.86 d/decade, respectively. The diurnal temperature range has decreased by 0.28 °C/decade. Both annual extreme low and high temperatures exhibit significant increasing trend, with the former clearly larger than the latter. For precipitation indices, regional annual total precipitation shows an increasing trend and most other precipitation indices are strongly correlated with annual total precipitation. Average wet day precipitation, maximum 1-day and 5-day precipitation, and heavy precipitation days show increasing trends, but only the last is statistically significant. A decreasing trend is found for consecutive dry days. For all precipitation indices, stations in northwestern Xinjiang have the largest positive trend magnitudes, while stations in northern Xinjiang have the largest negative magnitudes. 相似文献
15.
16.
Based on daily maximum and minimum temperature observed by the China Meteorological Administration at 115 meteorological stations in the Yangtze River Basin from 1962 to 2011,the methods of linear regression,principal component analysis and correlation analysis are employed to investigate the temporal variability and spatial distribution of temperature extremes.Sixteen indices of extreme temperature are selected.The results are as follows:(1) The occurrence of cold days,cold nights,ice days,frost days and cold spell duration indicator has significantly decreased by –0.84,–2.78,–0.48,–3.29 and –0.67 days per decade,respectively.While the occurrence of warm days,warm nights,summer days,tropical nights,warm spell duration indicator and growing season length shows statistically significant increasing trends at rates of 2.24,2.86,2.93,1.80,0.83 and 2.30 days per decade,respectively.The tendency rate of the coldest day,coldest night,warmest day,warmest night and diurnal temperature range is 0.33,0.47,0.16,0.19 and –0.07℃ per decade,respectively.(2) The magnitudes of changes in cold indices(cold nights,coldest day and coldest night) are obviously greater than those of warm indices(warm nights,warmest day and warmest night).The change ranges of night indices(warm nights and cold nights) are larger than those of day indices(warm days and cold days),which indicates that the change of day and night temperature is asymmetrical.(3) Spatially,the regionally averaged values of cold indices in the upper reaches of the Yangtze River Basin are larger than those in the middle and lower reaches.However,the regionally averaged values of most warm indices(except warm spell duration indicator) and growing season length in the middle and lower reaches are larger than those in the upper reaches.(4) The extreme temperature indices are well correlated with each other except diurnal temperature range. 相似文献
17.
It is important to examine the lateral shift rate variation of river banks in different periods. One of the challenges in this regard is how to obtain the shift rate of river banks, as gauging stations are deficient for the study of river reaches. The present study selected the Yinchuan Plain reach of the Yellow River with a length of 196 km as a case study, and searched each point of intersection of 153 cross-sections(interval between two adjacent cross-sections was 1.3 km) and river banks in 1975, 1990, 2010 and 2011, which were plotted according to remote sensing images in those years. Then the shift rates for the points of intersection during 1975–1990, 1990–2010 and 2010–2011 were calculated, as well as the average shift rates for different sections and different periods. The results show that the left bank of the river reach shifts mostly to the right, with the average shift rates being 36.5 m/a, 27.8 m/a and 61.5 m/a in the three periods, respectively. Contemporarily, the right bank shifts mostly to the right in the first period, while it shifts to the left in the second and third periods, with the average shift rates being 31.7 m/a, 23.1 m/a and 50.8 m/a in the three periods, respectively. The average shift rates for the left and right banks during the period 1975–2011 are 22.3 m/a and 14.8 m/a, respectively. The bank shift rates for sections A, B and C are different. The shift rate ratio of the left bank in the three sections is 1:7.6:4.6 for shift to the left and 1:1.7:3.8 for shift to the right, while that of the right bank is 1:1.8:1.2 for shift to the left and 1:5.6:17.7 for shift to the right during the period 1975–2011. Obviously, the average shift rate is the least in section A, while it is maximum in section B for shift to the left and in section C for shift to the right. The temporal variation of the shift rate is influenced by human activities, while the spatial variation is controlled by the local difference in bank materials. 相似文献
18.
《寒旱区科学》2021,13(4)
Ecophysiological responses to drought stress of Populus euphratica in Alashan Desert Eco-hydrology Experimental Research Station were investigated. Results show that under mild and moderate drought stress, stomatal length, aperture,area and density is likely to decrease in the early days, but afterwards this is likely to recovery with treatment over the passage of treatment time. Under severe drought stress, these properties appear to decline continuously. However, after45 days of drought-stress treatment, the decline is not as noticeable as before, indicating that Populus euphratica could possibly reduce water evaporation by shutting down the stoma, leading to an improvement in its water use efficiency with better survival under drought stress conditions. The leaf area first decreases, and then increases under mild and moderate drought stress conditions, with the average values under different degree of stress found to be approximately 129.52,120.08, 116.63 and 107.28 cm2, respectively. Under moderate stress conditions, the leaf water potential appears to show a continuous decline where the average values under different degree of stress are found to be-1.27,-1.85,-4.29 and-4.80 MPa, respectively. In terms of proline content, the results demonstrate that this factor appears to increase significantly under moderate and severe drought stress conditions. Especially under severe drought stress condition, the content is found to be more than 700 μg/g. Ranging over average values of 14.64 and 15.90 nmol/g under moderate and severe drought stress, respectively, Malondialdehyde content is found to increase quite rapidly under moderate and severe drought stress conditions at first, which then appears to decrease gradually with the treatment over time. 相似文献
19.
西北地区山区融雪期气候变化对径流量的影响(英文) 总被引：5，自引：0，他引：5
Water resources in the arid land of Northwest China mainly derive from snow and glacier melt water in mountainous areas. So the study on onset, cessation, length, tempera-ture and precipitation of snowmelt period is of great significance for allocating limited water resources reasonably and taking scientific water resources management measures. Using daily mean temperature and precipitation from 8 mountainous weather stations over the pe-riod 1960?2010 in the arid land of Northwest China, this paper analyzes climate change of snowmelt period and its spatial variations and explores the sensitivity of runoff to length, temperature and precipitation of snowmelt period. The results show that mean onset of snowmelt period has shifted 15.33 days earlier while mean ending date has moved 9.19 days later. Onset of snowmelt period in southern Tianshan Mountains moved 20.01 days earlier while that in northern Qilian Mountains moved only 10.16 days earlier. Mean precipitation and air temperature increased by 47.3 mm and 0.857℃ in the mountainous areas of Northwest China, respectively. The precipitation of snowmelt period increased the fastest, which is ob-served in southern Tianshan Mountains, up to 65 mm, and the precipitation and temperature in northern Kunlun Mountains increased the slowest, an increase of 25 mm and 0.617℃, respectively, while the temperature in northern Qilian Mountains increased the fastest, in-creasing by 1.05℃. The annual runoff is also sensitive to the variations of precipitation and temperature of snowmelt period, because variation of precipitation induces annual runoff change by 7.69% while change of snowmelt period temperature results in annual runoff change by 14.15%. 相似文献
20.
Based on daily maximum and minimum temperature observed by the China Mete- orological Administration at 115 meteorological stations in the Yangtze River Basin from 1962 to 2011, the methods of linear regression, principal component analysis and correlation analysis are employed to investigate the temporal variability and spatial distribution of tem- perature extremes. Sixteen indices of extreme temperature are selected. The results are as follows： （1） The occurrence of cold days, cold nights, ice days, frost days and cold spell du- ration indicator has significantly decreased by -0.84, -2.78, -0.48, -3.29 and -0.67 days per decade, respectively. While the occurrence of warm days, warm nights, summer days, tropi- cal nights, warm spell duration indicator and growing season length shows statistically sig- nificant increasing trends at rates of 2.24, 2.86, 2.93, 1.80, 0.83 and 2.30 days per decade, respectively. The tendency rate of the coldest day, coldest night, warmest day, warmest night and diurnal temperature range is 0.33, 0.47, 0.16, 0.19 and -0.07~C per decade, respectively （2） The magnitudes of changes in cold indices （cold nights, coldest day and coldest night） are obviously greater than those of warm indices （warm nights, warmest day and warmest night）. The change ranges of night indices （warm nights and cold nights） are larger than those of day indices （warm days and cold days）, which indicates that the change of day and night tem- perature is asymmetrical. （3） Spatially, the regionally averaged values of cold indices in the upper reaches of the Yangtze River Basin are larger than those in the middle and lower reaches. However, the regionally averaged values of most warm indices （except warm spell duration indicator） and growing season length in the middle and lower reaches are larger than those in the upper reaches. （4） The extreme temperature indices are well correlated with each other except diurnal temperature range. 相似文献