1961-2017年青海高原降雪时空变化分析研究

基于1961-2018年青海高原47个台站观测资料,分析了青海高原降雪量、降雪日数的时空演变特征,结果表明：青海高原地区降雪量呈明显的减少趋势,每10年减少3.7 mm,其中1981-1989年、1990-1999年为降雪量偏多期,2000年以来为降雪量偏少期;近57年来青海高原降雪平均日数为11～43 d,青海高原降雪日数及各量级降雪日数总体均无明显趋势性变化,但存在阶段性变化;青海高原降雪量及降雪日数除常年干旱区柴达木盆地均为低值区外,其余地区高海拔地区多于低海拔地区,南部多于北部;青海高原月平均降雪量呈“U”型分布,而月平均降雪日数呈单峰型分布,降雪日数在冬季中末期偏多,春季偏少,其中小雪以上量级降雪日数易发生在秋末冬初,冬末向春季转换的时段内;近57年来青海高原降雪量在2002年前后存在明显的突变现象,其中青南牧区、青海湖地区及东部农业区年降雪量分别在2001年,1996年以及1996年前后存在明显突变现象,柴达木盆地降雪量无明显突变现象;而青海高原降雪日数在2000年前后存在明显突变现象,其中青南牧区1980年、2001年前后存在明显的突变现象,其余3个地区降雪日数无明显突变现象。     

1961 - 2018年青海高原昼夜雨量时空变化特征分析

基于青海高原1961 - 2018年47个气象站昼夜雨量数据, 分析了青海高原及各生态功能区的昼夜雨量及雨日的时空变化特征。结果表明： 近58年来, 青海高原昼夜雨量空间分布基本一致, 总体表现为东南向西北减少, 夜雨日多于昼雨日分布。青海高原昼夜雨量总体均呈增多趋势, 昼雨量的增加速率大于夜雨量; 从空间分布来看, 柴达木盆地西部、 东部农业区大部及青南牧区南部少数地区昼夜雨量呈减少趋势, 而柴达木盆地东部、 环青海湖地区、 青南牧区大部昼夜雨量均呈增多趋势。青海高原昼雨日略有增加, 夜雨日有减少趋势; 在地域上, 柴达木盆地昼夜雨日增多趋势明显, 而东部农业区昼夜雨日减少趋势明显。青海高原昼夜雨量分别呈2 a、 3 a的周期。近58年来, 青海高原、 东部农业区、 环青海湖地区、 柴达木地区昼雨量均无明显的突变现象, 仅青南牧区昼雨量在2003年前后存在明显突变现象; 青海高原、 东部农业区、 青南牧区夜雨量无明显突变现象, 环青海湖地区、 柴达木盆地夜雨量分别在1979年、 2003年出现了突变现象。     

The changing characteristics of drought in China from 1982 to 2005

Drought is one of the most detrimental natural disasters. Studying the changing characteristics of drought is obviously of great importance to achieve the sustainable use of water resources at river basin scales. In this paper, the satellite-based Vegetation Condition Index (VCI) and Vegetation Health Index (VH) were firstly calculated by using NDVI and brightness of the Global Vegetation Index dataset derived from Advance Very High Resolution Radiometer for China in growing seasons over 1982–2005. Then, the long-term VCI and VH data were employed to study the variation of droughts in the ten basins covering the whole country. The linear trend of each pixel showed that most parts of China were getting wetter in growing seasons, and the drought areas defined by the number of drought pixels have decreased in most basins. The increasing trend of basin averaged values of VCI and VH also indicates the whole country was generally getting wetter. At last, to better understand the two remote sensing drought indices, the response of the growing-season VCI and VH was compared to that of the Palmer Drought Severity Index and 6-month Standard Precipitation Index. Significant spatial variability of the relationship between the VCI, VH, and the station-based meteorological drought indices was shown, and some more closely related areas were found. The study will be useful for water resources management for each basin in the future.     

1961-2010年青藏高原降水时空变化特征分析

利用青藏高原69个气象台站的降水量资料,采用旋转经验正交函数分析（REOF）、线性趋势分析和累积距平法,系统地研究了1961-2010年青藏高原降水的时空变化规律,揭示了青藏高原不同区域降水变化的差异性.研究表明：近50 a来青藏高原降水量总体呈现增加趋势,增长率为6.7 mm·（10a）^-1;青藏高原降水季节分配极不均匀,雨季和旱季非常明显,雨季降水占有主导作用;青藏高原降水由东南向西北递减,而且年际变化具有一定的多元化特征;青藏高原降水量变化空间分布差异显著,采用REOF法将整个高原划分为10个小区,每个小区降水变化都具有不同的特征,除了青海东北部区和青海东南部-川北区降水呈减少趋势外,其他8个小区降水均呈增加趋势.     

Socioeconomic effect of dust storms in Kuwait

Kuwait is an arid country with an annual average rainfall of about 110 to 120 mm. Hence, dust storms have become a common environmental crisis. Although the dry summer months commonly have more dust storms, in recent years, dust storms occur more frequently in the spring season as well. Accumulated data of dust storms in Kuwait for the past 14 years (2001–2014) showed that the month of March had the highest number of dust storms (total 19), which is rather unusual, with an average of 8 dust storms per year (year 2008 had the highest dust storms of total 22). This study explored four socioeconomic effects of dust storms in Kuwait, specifically traffic accident rates, oil export loss due to close out of marine terminals, airline delays due to airport operation shutdown, and agriculture degradation. Statistical analysis using t test and Pearson correlation showed no apparent relationship between dust storms and traffic accident rates or agricultural production; however, loss of oil export and flight delay cost were affected by dust storms. There has been very few published research on the socioeconomic impact of dust storms; this is the first paper that explores the detailed socioeconomic effect of dust storms in Kuwait.     

1961 - 2017年中国东北地区降雪时空演变特征分析

利用东北地区162个气象台站逐日降水量和天气现象数据, 采用统计分析方法, 对近57年（1961 - 2017年）降雪的气候特征和时空演变规律进行了分析。结果表明： 降雪量和降雪日数最多出现在12月, 小雪和中雪最多出现在11月或12月, 大雪和暴雪在冬末春初出现概率最高。降雪分布为山地大于平原, 平原地区自北向南、 自东向西减少, 降雪高值区主要位于大兴安岭北部、 小兴安岭和长白山区, 降雪强度中心位于长白山区和辽宁中部平原地区。年、 秋季、 冬季、 春季降雪量占同期降水量比例分别为4.7%、 7.0%、 84.4%和7.6%; 辽宁省西部山区和南部大连地区日最大降雪量占年总降雪量比例最高, 最长连续降雪日数在2 d以下, 降雪较高纬度地区更为集中。近57年降雪量和降雪强度分别以1.93 mm?（10a）^-1和0.11 mm?d^-1?（10a）^-1的速率显著增加, 降雪日数以2.08 d?（10a）^-1速率显著减少; 降雪量增加主要表现为各等级降雪量的增加, 降雪日数减少主要是微量和小雪日数的减少, 降雪强度增加主要为大雪和暴雪降雪强度的增加。年、 秋季和冬季降雪量占同期降水量比例平均每10年增加0.36%、 0.48%和0.45%, 春季以0.11%?（10a）^-1的速率减少。中雪、 大雪和暴雪对降雪贡献率均呈增加趋势, 小雪降雪量和微量降雪日数贡献率减少; 1987年降雪量和降雪日数突变后, 微量降雪日数和暴雪日数、 小雪降雪量贡献率改变显著。就区域平均而言, 2001 - 2017年的降雪量较1961 - 1980年增加了27.8%, 降雪日数减少了22.4%。     

阿拉善高原盐湖水化学特征的主成分分析研究

运用数理统计的主成分分析法对阿拉善高原腾格里沙漠地区和巴丹吉林沙漠地区的21个盐湖、八种水化学特征变量进行研究,获得四个可以揭示水化学特征的主成分及相应的数学模型,进一步得出各盐湖在四个新的主成分变量上的得分值,从而解释八种水化学成分变量与盐湖类型之间的相关信息。     

Impacts of climate change on aridity index and its spatiotemporal variation in the Loess Plateau of China,from 1961 to 2014

The Loess Plateau, the transitional zone between humid and arid regions of China, is an important region to examine the regional hydrological cycle and variation in humid and arid regions under global climate change. Aridity index (AI), the ratio of precipitation (P) to potential evapotranspiration (ET₀), is an important indicator of regional climate conditions and is also used to classify drylands. In this study, data from 51 national meteorological stations during the period of 1961–2014 were collected to estimate the AI in the Loess Plateau. Results show that a downward trend in annual AI was detected and the boundary of the drylands region based on the AI was expanded across the Loess Plateau over the period of 1961–2014. The spatiotemporal variability of P was the main cause in the AI variations. Furthermore, data analysis suggested the occurrences of the extreme minimum AI values were mostly affected by fluctuations of the two factors (ET₀ and P) rather than its corresponding trend during the period. Thus, this study indicated the major driving factor of AI and the relationship between extreme AI values and the global climate anomalies in the Loess Plateau region, and meanwhile, provided an understanding of the impacts of climate change on hydrological cycle in the Loess Plateau of China.     

1961—2019年青藏高原中东部夏季强降水与大尺度环流的关系

采用一元线性回归、合成分析等方法对1961—2019年青藏高原中东部71个站点夏季强降水与大尺度环流进行了分析,研究结果表明,近年来青藏高原中东部强降水呈增加趋势。在强降水高值年时,青藏高原中东部水汽辐合加强,中纬度西风和热带地区东风带向极移动加强,高层辐散流场、水汽输送以及上升运动条件,共同作用导致了强降水的产生。在强降水低值年时,青藏高原中东部大部水汽异常辐散,区域内的季风水汽输送减弱,西风带和东风带均向赤道移动减弱,高层为气旋式环流异常。通过风暴轴、波作用通量和E-P通量进一步分析发现,当北大西洋地区风暴轴偏强（偏弱）时,瞬变扰动作用加强（减弱）,使得北大西洋地区高纬度西风加速（减弱）,急流出口区的不稳定能量激发了欧洲西北部的异常反气旋（异常气旋）,并通过Rossby波列调控季风输送,导致了青藏高原中东部地区强降水的变化。     

1961-2005年新疆博州地区农业热量因子的时空变化

利用Mann-Kendall检验法分析了新疆博州地区1961-2005年的气候生长期、无霜期、大于10 ℃活动积温、夏秋季平均气温、 夏半年炎热天气等农业热量因子的时空变化特征. 结果表明: 1)博河上游地区1981-2005年25 a气候生长期缩短了7.8 d;博河中游与艾比湖以南地区1961-2005年45 a气候生长期分别延长12.4 d 和6.7 d;2)博河上游地区终霜显著提前, 25 a间无霜期延长了17.0 d, 博河中游与艾比湖以南地区初霜显著推迟, 45 a里无霜期分别延长了15.8 d和13.5 d. 3)≥10 ℃活动积温初日普遍提前, 终日普遍后推, 积温累积值普遍增加;博河上游一带25 a≥10 ℃活动积温持续期延长了16.5 d, 博河中游与艾比湖以南地区45 a间分别延长了17.6 d与4.5 d;4)艾比湖以南地区6-8月里的炎热天气平均以0.8～1.1 d·(10a)-1的速率显著增加, 年炎热天气平均以3.2 d·(10a)-1左右的速率增加;5)博河上、中游与艾比湖以南地区夏秋季(8-9月)平均气温分别以0.20、 0.40、 0.17 ℃·(10a)-1的速率增加;6)博州农业热量"高值中心"强度增加不大, 但高值区域扩大化, 离高值区越远, 变幅越大.     

Simulation Study on Precipitation Recycling Ratio in the Tibetan Plateau from 1982 to 2005

A dynamical downscaling approach using a regional climate model WRF (Weather Research and Forecasting Model Vision 3.5) driven by a global climate model CCSM4 (The Community Climate System Model Version 4) was adopted, and the downscaling results for the historical period (1982-2005) were evaluated for annual mean precipitation rate and evaporation rate over the Tibetan Plateau (TP). Furthermore, the spatial distribution and seasonal variation characteristics of Precipitation Recycling Ratio (PRR) simulated by CCSM4 and WRF were analyzed with the QIBT (Quasi-isentropic Back-trajectory method). The results show that the historical spatial distributions of annual mean precipitation rate and evaporation rate over the TP were found to better reproduce in the dynamical downscaling modeling compared to its coarse-resolution forcing. The PRR of the TP is 32% simulated by WRF, with a higher PRR in the wet season and a lower PRR in the dry season for the river basins in the northern TP, but the opposite seasonal variation was found for the river basins in the southern TP. In addition, the different land covers over the TP are more precisely represented in the WRF model, the PRR of grassland, shrubland and sparsely vegetation is higher than that of other land cover types.     

1961-2015年我国鲁东南地区降雪的气候特征分析

利用鲁东南地区18个代表站1961-2015年的逐日降水量、逐日天气现象、积雪深度资料,对近55 a来降雪的气候特征进行了统计分析。结果表明：鲁东南地区年均降雪日数、强降雪日数、降雪量、强降雪量及年均雪深、年最大积雪深度的空间分布总体上山区多于平原和沿海,区域差异明显。21世纪00年代以前为多雪时期,以后为少雪时期。近55 a的年均降雪日数、强降雪日数、降雪量、强降雪量及年均雪深、年最大积雪深度皆呈减少趋势,降雪由多转少的转折年份均在1993年,年均雪深、年最大积雪深度的减少分别出现在1987年、1986年。鲁东南地区降雪主要集中在1-2月份,3月份强降雪量最大,平均雪深、最大积雪深度的最大月份分别出现在11月份、3月份。降雪时段为10月23日-次年4月28日,降雪的初终日西北部山区皆为最早。降雪日数、强降雪日数、降雪量、强降雪量、雪深均存在3 a的周期,最大积雪深度存在4～5 a的周期。     

黄土高原区域尺度土壤干燥化的空间和季节分布特征

为掌握黄土高原土壤干燥化程度的空间分布特征,定量评价雨季前、后土壤干燥化程度,于2013年在黄土高原南北方向布设一条样带（N=86）,获取雨季前、后0~5 m剖面土壤含水量。采用地统计学方法分析了土壤干燥化指数的空间分布规律及变异特征。结果表明:在黄土高原地区,土壤干燥化程度存在明显的纬度地带性,且雨季前土壤干燥化指数的空间变异程度高于雨季后;经过雨季降水的补给,土壤干层在一定程度上得到修复,且中部地区的修复效果明显优于南部及北部地区;土壤干燥化指数剖面分布特征在雨季前、后的差异主要表现在浅层0~2.3 m土层,这主要归因于降水对浅层土壤水分的补给。     

Long-term impacts of dust storms on transport systems in south-eastern Iran

Natural Hazards - Dust storms are frequent in the Sistan region of south-eastern Iran and cause a wide range of problems, but few studies have assessed their negative impacts. This paper makes an...     

Definition and temporal evolution of the heat and cold waves over the Spanish Central Plateau from 1961 to 2010

The temporal behavior of the annual frequency of heat and cold waves observed between 1961 and 2010 is established for the Spanish Central Plateau and for the two sub-areas in it. The series of daily maximum and minimum temperature anomalies for the working areas were calculated from the daily data concerning temperature anomalies. The thresholds of these series of anomalies, determined by the P₁₀ and P₉₀ percentiles values, were obtained. Heat waves occur when there are two or more consecutive days on which the maximum and minimum temperature anomalies are simultaneously greater than the values of the thresholds obtained for the P₉₀ percentile. The heat waves that affected the Spanish Central Plateau and the two sub-areas during the period of time considered were identified and their monthly and annual frequencies were obtained. Likewise, a cold wave is considered to have occurred when there are two or more consecutive days on which the maximum and minimum temperature anomalies are simultaneously lower than the thresholds established by the corresponding P₁₀ percentiles. The cold waves occurring in the study area were identified and their monthly and annual frequencies in the study period were established. According to the results, the months with highest number of heat waves between 1961 and 2010 were May (25 waves) and June (23 waves). Trend analysis of the series of annual frequencies indicates that there was an increasing trend towards the occurrence of heat waves, with a confidence level greater than 99%. The linear model established indicates that an increase had occurred in the frequency of heat waves in the Spanish plateau of the order of 0.6 waves every 10 years. Regarding cold waves, these were detected in each month of the year and their frequency ranged between eight and 16 events per year. The months with lowest number of cold waves were April (nine), July (eight) and August (nine), and the months with the highest number were March, May, June and October, with 16 cold waves. The years with the highest number of cold waves were 1969, 1971 and 1977, with seven cases. In the other years the annual rate was between one and six. Trend analysis of the series of annual frequencies indicated that there was a decreasing frequency of cold waves, at the confidence level of 99%. When a linear model was considered for the Spanish Central Plateau a decreasing frequency of the cold waves of the order of 0.54 waves in every 10 years was observed from 1961 to 2010.     

1961-2012年中国5类主要冰冻天气的气候及变化特征

利用1960/1961-2011/2012年中国有冰冻天气观测且序列完整的1 600多站逐日冰冻现象数据, 研究了中国地区冰冻天气的时空气候变化特征. 结果表明: 年平均霜日数超过180天的地区主要分布在青藏高原东北部、天山、大-小兴安岭一带. 霜日数在我国中北部和青藏高原地区以增加趋势为主, 长江流域及其以南地区为减少趋势. 全国平均的霜日数为显著增长趋势, 超过0.05的显著性水平, 线性增长率达到2.03 d·(10a)^-1, 霜日发生频率增强; 年平均积雪日数超过90 d的地区分布在青藏高原东北部、天山、大-小兴安岭一带. 积雪日数无明显时间变化趋势; 年平均结冰日数超过210 d的地区分布在青藏高原、大兴安岭及天山部分地区. 结冰日数全国范围以减少趋势为主. 全国平均结冰日数有明显的年代际变化趋势, 1980-1990年为结冰日数最多年份; 年平均雾凇日数超过30 d的地区主要在天山地区、大兴安岭地区以及四川峨眉山. 雾凇日数以减少趋势为主, 长江中下游部分地区有增加趋势. 全国平均雾凇日数有显著减少趋势, 超过0.01的显著性水平, 线性递减率达到0.60 d·(10a)^-1; 年平均雨凇日数主要分布在南方云贵高原地区以及长江中下游地区的一些高山区域. 雨凇日数在华北平原地区以减少趋势为主, 长江中下游地区部分站点有增加趋势. 全国平均雨凇日数随时间有弱的增加趋势.     

京津地区“沙尘暴”的性质和治理——以北京2006年4月16日的尘暴为例

依据粒度分析、电镜扫描、能谱分析、常温水溶盐检测、宏观表象特征研究和实地调查，证实北京2006年4月16日的所谓“沙尘暴”是尘暴，干涸盐湖是京津尘暴的重要源区。因此，要治理京津地区的尘暴，就必须修复干涸盐湖区的生态环境，而不能像过去那样去治理沙漠。要修复干涸盐湖区的生态环境，一定要用现代生态环境地质学的理论和方法去研究干涸盐湖区在地质历史时期植被演化的趋势，筛选出最适合当地生态环境的土著先锋植物种群，并用土著先锋植物种群对尘源区进行“地毯式”的覆盖，而不能用种树去阻挡它，因为再高的树林也挡不了从2000-3000m以上高空飘来的浮尘。     

阿拉善地块中元古代诺尔公群的构造变形特征

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