南疆近60 a来冰雹灾害时空变化特征分析

冰雹是新疆主要灾害性天气之一, 利用新疆南疆各地州1949-2008年发生的冰雹频次及其造成的受灾农田面积、 经济损失、 死亡牲畜等资料, 分析了南疆冰雹频次时空变化特征及各县市雹灾灾情.结果表明: 南疆冰雹发生频次近60 a间呈明显上升趋势, 1950年代至1980年代中期发生频次较低, 1986年开始发生频次显著上升, 至1991年达最高值, 由1996年起又减少到2003年谷底.冰雹发生主要集中在3-10月, 其中6月频次最多, 年均3.6次, 其次5月为3.1次. 巴州、 阿克苏、 喀什和克州以春末到夏季型降雹为主, 和田以春季型降雹为主.冰雹一天之内多发生在白天到傍晚时段, 持续时间多为1~20min. 南疆冰雹空间分布上西北部多于东南部, 山脉的背风坡多于迎风坡, 山间盆地多于开阔平原.对各地州而言, 阿克苏冰雹发生频次最多, 属于严重雹灾区; 喀什和巴州次于阿克苏, 属于重雹灾区; 克州与和田冰雹发生频次较少, 属于中雹灾区. 冰雹受灾农田面积和经济损失随着工农业生产总值的增长而增加, 而且增长速度比经济增长速度快. 建议加大防雹投入力度, 建立人工防雹系统, 以减少雹灾损失, 遏制工农业发达地区雹灾损失严重和随着国民经济的增长雹灾损失增加的现象.     

1961-2014年新疆冰雹灾害时空分布特征

通过整理、 普查得到1961-2014年新疆以县为单位的雹灾频次、 受灾面积、 经济损失的样本序列, 在此基础上定义了表征雹灾程度的无量纲数损失指数. 结果表明: 新疆雹灾频次集中出现在阿克苏地区、 博州、 石河子地区, 5-8月为多发期, 6月最多. 雹灾的年际变化呈现出2～5 a的短周期和7～8 a的长周期, 20世纪60、 70年代为新疆雹灾的少发期, 1980-1994年、 2001-2014年为雹灾的两个集中高发期. 按照地区累计灾损指数将新疆雹灾划分为5个等级, 阿克苏地区属严重雹灾区, 喀什地区、 塔城地区、 伊犁州属重雹灾区, 石河子地区、 博州、 昌吉州、 巴州、 克拉玛依市属中雹灾区, 阿勒泰地区、 克州、 和田地区、 哈密地区属轻雹灾区, 吐鲁番地区和乌鲁木齐市属微雹灾区.     

基于多普勒天气雷达的冰雹云早期识别与预警方法研究

利用C波段新一代多普勒天气雷达监测资料和探空数据,对新疆南疆阿克苏地区西部绿洲2009-2015年28个降雹个例、32个对流风暴降雹单体进行分析,把发生在该区域的暴雹单体分为弱、中、强等三种类型,并综合分析不同强度降雹单体的“初生”、“跃增”和“酝酿”三个冰雹云生命史关键阶段的空间分布、演变规律以及不同温度层之间的关系,筛选出了能够提前识别各类冰雹云的雷达回波特征参量及指标阈值,并以此作为判识因子,建立了三种冰雹云提前识别及预警概念模型,同时对其识别能力进行验证,获得了三类冰雹云80%以上的识别准确率和合适的早期识别与有效作业指挥时间提前量,为该区域强冰雹云的早期识别与有效实施人工防雹作业决策提供科学依据。     

中国西部降水中δD的初步研究

通过１９９６年夏半年中国西部６个站点降水中δＤ的空间变化特征和与气温变化关系的研究,结果表明,中国西部不同地区降水中δＤ的空间变化很大,青藏高原南部降水中δＤ较低,中国广大的西北内陆地区是降水中δＤ的一个高值区,远高于青藏高原南部地区,其空间变化未遵从“大陆效应”的规律．分析表明,这与中亚腹部干旱的气候条件和大陆内部的局地水汽循环有关．而且在大陆内部降水中δＤ对气温变化的敏感性很强,而在高原南部的季风区,降水中δＤ与气温无明显相关性．     

青藏高原冻融侵蚀敏感性评价与分析

冻融侵蚀是我国仅次于水蚀和风蚀的土壤侵蚀类型。青藏高原由于其海拔高、辐射强、气温低的特点,是我国冻融侵蚀较严重的区域。选择影响冻融侵蚀的5个主要因子：气温年较差、降水量、坡度、坡向、植被覆盖度进行定量研究,分析青藏高原冻融侵蚀敏感性强度及空间分布特征。结果表明：（1）青藏高原冻融侵蚀区面积为149.02×10⁴ km²,占青藏高原总面积的62.20%;冻融侵蚀敏感区的面积为56.80×10⁴ km²,中度及以上敏感区面积为27.39×10⁴ km²,占冻融侵蚀敏感区面积的48.22%;（2）冻融侵蚀敏感性空间分布差异明显,中度以上敏感区主要分布在青藏高原南部和东南部、喀喇昆仑山、祁连山、横断山区等地区。     

1983-2013年西藏自治区气象灾害时空分布特征与变化趋势

西藏自治区地处青藏高原这一独特的孕灾环境中,气象灾害的频发对当地农牧业、生态环境等敏感领域的影响尤为显著。通过收集西藏自治区1983-2013年气象灾害事件,分析了干旱、雪灾、霜冻、冰雹和洪涝五种灾害的年际、月际、空间分布特征。结果表明：在时间分布上,研究区五种气象灾害在1983-1995年发生总频次呈增涨趋势,1995年后趋于稳定,其中干旱多发生在3-6月,雪灾全年均有发生,霜冻多发生在4月、5月和8月,冰雹和暴雨洪涝灾害季节性强,主要发生在6-9月;在空间分布上,气象灾害高发区分布于西藏自治区南部,其中,干旱多发区分布于日喀则市中东部和山南市北部,雪灾多发区分布于那曲、阿里以及西藏自治区南部边缘地区,霜冻多发区分布于西藏自治区东、南部少数地区,冰雹频发区多呈带状且分布于雅鲁藏布江流域,暴雨洪涝多发区分布于西藏自治区中、东部河谷地带。基于历史气象灾害事件,开展西藏自治区气象灾害的时空分布特征及趋势研究,其结果对农业气象灾害预测预报,区域农业防灾减灾等具有重要的意义。     

新疆冰雹灾害经济损失评估及风险区划研究

基于1984-2014年新疆雹灾受灾面积、总成灾面积、农作物播种面积、新疆生产总值及以县为单位的雹灾频次等统计数据,构建雹灾经济损失指标和风险度指标,进行新疆冰雹灾害评估研究。其中雹灾经济损失指标可用于评价新疆雹灾经济损失的趋势变化,风险度指标可借助GIS空间信息处理技术形成新疆雹灾风险区划。研究表明：雹灾经济损失总体呈波动上升趋势,且受环境不稳定度的影响较大,二者保持着较好的正相关性。新疆冰雹灾害总体以中、低度风险为主,高风险次之。高风险区主要集中在喇叭形河谷地带的伊犁地区及其两侧的阿克苏、博州等地,建议通过调整农业产业结构、提升人工防雹能力等方式降低上述区域的雹灾损失。     

南水北调西线一期工程引水区和黄河上游区域气候特征分析

利用引水区和黄河上游地区25个站1951—2000年50 a的气温和降水逐日资料,分析了研究区域降水的时空分布特征;把引水区和黄河上游地区分成7个小区,利用小波分析的方法研究了各小区气温和降水的多时间尺度特征.结果表明:黄河上游和南水北调西线引水区夏、秋、冬三季降水以同步的变化为主,其次为黄河上游与引水区之间存在反位相的变化.春季降水主要表现为黄河上游与引水区之间存在反位相的变化,其次才表现为一致的变化.各区的气温均以同步升温为主.降水具准3 a和准22 a周期,气温的振荡周期主要是2~5 a的小周期和准11 a的周期.引水区和黄河上游地区近50 a来夏季的降水在一致变化的基础上也有着明显的区别.     

青海省近50年极端降水事件时空分布特征

基于线性倾向估计、小波分析、Mann-Kendall检验及空间插值等方法,对1962—2013年28个均匀分布在青海省内的气象站点数据近50 a(1962—2013年)极端降水事件的时空特征进行了分析。结果表明,在长期趋势上青海省极端降水事件呈上升趋势,其强度与频数变化分别具有28 a和15 a±的主周期,并且少数站点在20世纪90年代发生突变;青海省内的极端降水事件在空间上存在明显差异,整体呈自西向东逐渐增强的特征,极端降水事件在南部地区发生频率总体高于北部地区,东南部发生极端降水的频率最高;近50 a青海省内大部分地区极端降水事件的强度与频数均呈上升趋势,其中东北部地区极端降水事件的强度上升趋势较为明显,仅有东南端与西北端呈现下降趋势,极端降水事件频数的上升趋势由东南端及西北端分别向中部加强。     

黑河流域中上游地区降水δ18O变化特征

水资源短缺和合理利用是黑河流域面临的一个严峻问题,解决问题的关键就是要深入了解水循环过程.降水作为水循环中一个重要环节,分析其环境同位素变化特征是应用同位素示踪技术研究水循环过程所必须的前提.根据黑河流域中上游地区取得的降水水样和降水气象资料,分析了该区域降水中δ¹⁸O的变化特征.结果表明:降水δ¹⁸O受降水量、季节、高度和温度等众多因素综合影响,其中温度占主导地位;由于位于干旱内陆地区,降水中δ¹⁸O的季节变化幅度较大,可达20‰以上;降水δ¹⁸O与降水前后平均气温的相关性显著,分别高于δ¹⁸O与降水前气温或降水后气温的相关性.从空间上来看,山区或上游地区降水δ¹⁸O与气温之间的相关性显著,分别高于δ¹⁸O与山前或山前盆地的相关性.     

Evaluating factors responsible for contrasting signature of wasteland development in northern and southern Ganga Plains (Bihar State,India) with focus on waterlogging

The present study provides assessment of wasteland development in Bihar State based on satellite data. Wasteland covers 6.90 % (6,501 km²) of the state area and exhibits dominance of waterlogged areas in North Bihar (25.28 %) and scrubland (26.61 %) in South Bihar. The waterlogged areas in the state are dominantly associated with northern Bihar plains (94 %) with minor development (6 %) in southern Bihar plains. Such unequal distribution of waterlogged land areas in northern and southern Bihar plains is largely governed by high cumulative discharge generated in the large catchment area in Himalayan mountain ranges in the upland areas of northern Bihar plains in contrast to low cumulative discharge generated within small catchments in the Chota Nagpur Plateau in the southern Bihar plains. It is evaluated that the relief and groundwater level define the primary controlling factors, whereas rainfall, watershed area, and upland/plain ratio exert secondary control. Lower relief areas with high rainfall exhibit high soil moisture thereby inducing conditions of waterlogging. The study signifies the potential of satellite image-based evaluation of waterlogging through the use of Digital Elevation Model, Tropical Rainfall Measuring Mission-based rainfall measurement, and temporal waterlogging assessment together with other terrain parameters for conceptual understanding of waterlogging in northern Bihar plains.     

1980—2019年新疆南部不同强度暴雨洪水灾害的空间分布和时间变化特征

以1980—2019年新疆南部出现的暴雨洪水灾害事件造成的死亡人数、倒塌房屋数、倒塌棚圈数、牲畜死亡数、受灾面积作为灾情要素,采用比值权重法和无量纲化线性求和,构建了暴雨洪水灾害事件的灾损指数。根据灾损指数,采用百分位数法将每次暴雨洪水灾害事件定量划分为一般、较重、严重、特重四个等级。结果表明：新疆南部暴雨洪水事件在塔里木盆地北缘多于南缘,西部多于东部,高值区集中在阿克苏地区、喀什地区、克孜勒苏柯尔克孜自治州一带;暴雨洪水事件多发在3—10月,年出现次数呈现明显上升趋势,增幅为8次·（10a）^-1,主要表现为一般性灾害发生频次的增加;新疆南部暴雨洪水灾害年平均灾损指数在1985年和1999年发生两次突变,平均值表现出“低—高—低”阶段性变化;暴雨洪水灾害发生次数与3—10月降水量、大雨发生日数、暴雨发生日数密切相关。近40年来新疆南部降水量的增多,导致暴雨洪水灾害次数增加;年平均灾损指数与特重和严重灾害发生次数关系密切,后者对其贡献率达87%。     

基于灾情数据的新疆雪灾的评估与区划

选取1955-2017年新疆因雪灾造成的牲畜受灾数量、作物受灾面积、经济损失三大灾情数据,揭示新疆雪灾时间和空间分布特征,通过构建雪灾灾损指数,对新疆雪灾进行区划。分析表明：新疆雪灾的发生北疆多于南疆,山区多于盆地,西部多于东部,主要集中发生在阿尔泰山区、天山山区及昆仑山区,灾情最重的是阿勒泰地区、伊犁地区、塔城地区;进入2000年以后,雪灾呈现明显高位震荡特点;利用多指标综合评估法,运用连续型随机变量分布密度近似求法,求得的新疆雪灾灾损指数,能客观反映新疆雪灾灾情;雪灾灾损指数遵从Γ分布,根据Γ分布函数属性及各类雪灾事件发生概率,进行了新疆雪灾等级区划。研究成果可为决策服务及气候可行性论证提供理论依据,对科学准确地制定防灾备灾措施、及时组织开展雪灾应急救助工作以及灾后的恢复重建决策给予一定参考。     

Hydrochemical and isotopic characteristics of groundwater in the northeastern Tennger Desert,northern China

Groundwater is typically the only water source in arid regions, and its circulation processes should be better understood for rational resource exploitation. Stable isotopes and major ions were investigated in the northeastern Tengger Desert, northern China, to gain insights into groundwater recharge and evolution. In the northern mountains, Quaternary unconsolidated sediments, exposed only in valleys between hills, form the main aquifer, which is mainly made of aeolian sand and gravel. Most of the mountain groundwater samples plot along the local meteoric water line (LMWL), with a more depleted signature compared to summer precipitation, suggesting that mountain groundwater was recharged by local precipitation during winter. Most of the groundwater was fresh, with total dissolved solids less than 1 g/L; dominant ions are Na⁺, SO₄ ^2? and Cl^?, and all mineral saturation indices are less than zero. Evaporation, dissolution and cation exchange are the major hydrogeochemical processes. In the southern plains, however, the main aquifers are sandstone. The linear regression line of δD and δ ¹⁸O of groundwater parallels the LMWL but the intercept is lower, indicating that groundwater in the plains has been recharged by ancient precipitation rather than modern. Both calcite and dolomite phases in the plains groundwater are close to saturation, while gypsum and halite can still be dissolved into the groundwater. Different recharge mechanisms occur in the northern mountains and the southern plains, and the hydraulic connection between them is weak. Because of the limited recharge, groundwater exploitation should be limited as much as possible.     

Characteristics analysis for the flash flood-induced debris flows

Typhoon Haitang caused landfall on Taiwan during 15–21 July, 2005 and brought 2,279 mm of maximum cumulative rain with a maximum intensity of 176 mm/h. The torrential rain was mainly distributed from the central mountain range to southern Taiwan and triggered 222 slopeland-related hazards. Among the hazard events, there were 17 debris flows, 157 cases of traffic cut-off, three large-magnitude deep-seated landslides, and 10 villages isolated in the off-track mountainous areas. The debris flows initiated in southern Taiwan were associated with torrential rain, short channel length (<2 km), and small basin area (<3 km²), and were speculated to be induced by flash flood. These flash flood-induced debris flows have a higher rainfall intensity-duration threshold for initiation than in other areas. The deep-seated landslides, isolated villages due to traffic cut-off in off-track mountain areas, and recurrent hazards in areas affected by the M_L 7.6 Chi-Chi earthquake in 1999 are characteristics of slopeland hazards in Taiwan in recent years. One of the most urgently needed mitigation strategies in response to slopeland hazards is the plan for enhancing self-rescue disaster resistance in off-track mountainous villages in Taiwan.     

Hazard Assessment of Cold and Hot Damage for Double-Season Early Rice (DSER) in Lower-Middle Reaches of the Yangtze River Basin

Cold and hot damages which are both common disasters occurring in DSER growth time in lower-middle reaches of the Yangtze River Basin harm early rice. The two disasters occurrence should be deeply studied to protect the DSER yield. This study was based on meteorological data of 48 agricultural meteorological stations during 1961-2010 period and agricultural meteorological data during 1981-2010 for DSER in lower-middle reaches of the Yangtze River Basin. In this study, the growth time was divided into several phases according to the growth stage, including tillering stage, booting stage, flowering stage and filling stage. The disasters taking place at some stages was identified by building new judging standard and their intensity value was calculated by harm accumulated temperature calculation model. Fisher optimal division method was used to classify the disasters and H-P filter was used to consider the reduction of the yield. It was conducted to analize the disasters’ characteristics in growing season, the intensity of hazard and the weight of hazard at each stage by judging and quantifying cold and hot damage and developing hazard assessment model of disasters. All findings were displayed in maps by GIS technology. The results showed that: ①New disaster judging standard was more suitable for DSER and the hazard assessment model could reveal the disaster situation in lower-middle reaches of the Yangtze River Basin. ②Cold damage was severe at tillering stage while hot damage was severe at filling stage. In the view of the distribution of the decadal disaster intensity, cold damage became to be weak and hot damage became to be strong. Compared with the plains, mountainous region and hilly ground were attacked by cold damage frequently and hot damage rarely from the perspective of spatial distribution of disasters. Distinctly, plains near large areas of water were often harmed by cold damage at booting and flowering stage. ③The area of high hazard value and high disasters value at each stage were overlapped by each other roughly. Studying the hazard of the whole growth season showed that the highest hazard value was in Zhejiang province, and the next in Hubei Province. So Hu’nan and Jiangxi Provinces were quite suitable to grow DSER. ④In contrast with the hazard weight at each stage, the vulnerable phases of the whole growth time were in sequence of filling stage> tillering stage> flowering stage > booting stage. What’s more, aiming at defensing and fending off risk, some special stages in special province should be paid close attention including booting and filling stages in Hubei Province, tillering and flowering and filling stages in Hu’nan Province, tillering and filling stages in Jiangxi Province, flowering and filling stages in Zhejiang Province. The conclusion can be taken as theoretical basis for the government management of agricultural production, disaster prevention and mitigation.     

基于灾损评估的青海高原冰雹灾害风险区划

利用青海高原1961-2010年42个气象站逐次冰雹过程及其灾情信息, 采用滑动平均、 标准归一化及线性回归等方法, 在分析致灾因子危险性、 承灾体易损性评估指标的基础上, 建立了冰雹灾害区划模型, 并结合ArcGIS9.3平台得到青海高原冰雹灾害风险区划图. 结果表明: 青海东部农业区、 环青海湖地区、 柴达木盆地东部及三江源地区中东部为易受冰雹灾害影响的特高风险或高风险区域; 祁连山地区为中风险区, 而低风险区则位于柴达木盆地中、 西部. 区划结果与历史冰雹灾情基本吻合, 旨在为该区防灾减灾提供科学依据.