The Warming and Wetting Ecological Environment Changes over the Qinghai-Tibetan Plateau and the Driving Effect of the Asian Summer Monsoon

The impact of warming and wetting on the ecological environment of the Qinghai-Tibet Plateau(TP)under the background of climate change has been a concern of the global scientific community.In this paper,the optimized interpolation variational correction approach is adopted for the analysis of monthly high-resolution satellite precipitation products and observations from meteorological stations during the past 20 years.As a result,the corrected precipitation products can not only supplement the“blank area”of precipitation observation stations on the TP,but also improve the accuracy of the original satellite precipitation products.The precipitation over the TP shows different spatial changes in the vegetation growing season,known as the time from May to September.The precipitation in the vegetation growing season and leaf area index(LAI)in the following month show a similar change pattern,indicating a“one-month lag”response of LAI to precipitation on the TP.Further analysis illustrates the influence of water vapor transport driven by the Asian summer monsoon.Water vapor derived from trans-equatorial air flows across the Indian Ocean and Arabian Sea is strengthened,leading to the increase of precipitation in the central and northern TP,where the trend of warming and wetting and the increase of vegetation tend to be more obvious.By contrast,as a result of the weakening trend of water vapor transport in the middle and low levels in southern TP,the precipitation decreases,and the LAI shows a downtrend,which inhibits the warming and wetting ecological environment in this area.

ROLE OF A WARM AND WET TRANSPORT CONVEYOR OF ASIAN SUMMER MONSOON IN A BEIJING HEAVY RAINSTORM ON JULY 21,2012

A heavy rainstorm named Beijing "7.21"heavy rainstorm hit Beijing on 21 to 22 July 2012, which is recorded as the most severe rainstorm since 1951. The daily precipitation amount in many stations in Beijing has broken the history record. Based on the NCAR/NCEP reanalysis data and precipitation observation,the large-scale conditions which caused the "7.21"heavy rainstorm are investigated, with the emphasis on the relationship between it and an equatorial convergence zone, Asian summer monsoon as well as the tropical cyclone over the ocean from the Philippines to the South China Sea(SCS). The results indicated that a great deal of southerly warm and wet moisture carried by northward migrating Asian summer monsoon provided plenty of moisture supplying for the "7.21"heavy rainstorm. When the warm and wet moisture met with the strong cold temperature advection induced by cold troughs or vortexes, an obviously unstable stratification formed, thus leading to the occurrence of heavy precipitation. Without this kind of intense moisture transport, the rainstorm only relying on the role of the cold air from mid-and higher-latitudes could not reach the record-breaking intensity. Further research suggested that the northward movement of an Asian monsoonal warm and wet moisture transport conveyor(MWWTC) was closely related with the active phase of a 30-60 day intra-seasonal oscillation of the Asian summer monsoon. During this time, the monsoon surge triggered and maintained the northward movement of the MWWTC. In addition, compared with another heavy rainstorm named"63.8"heavy rainstorm, which occurred over the Huaihe River Basin in the mid-August 1963 and seriously affected North China, a similar MWWTC was also observed. It was just the intense interaction of the MWWTC with strong cold air from the north that caused this severe rainstorm.

Strengthening the three-dimensional comprehensive observation system of multi-layer interaction on the Tibetan Plateau to cope with the warming and wetting trend

青藏高原的水循环变化对于高原及其下游区域人类的生产生活具有举足轻重的影响.在高原暖湿化的背景下,其水文循环加快,极端天气和自然灾害事件概率增大,比如,雪灾,洪水,滑坡,泥石流,冰崩在山区频发.因此,如何准确的估算青藏高原水循环各分量的大小及变化幅度是评估高原环境变化影响亟需解决的科学问题.根据水在各圈层间转换过程,我们提出了建立第三极地区(尤其是复杂山区)的三维立体多圈层地气相互作用综合观测系统(包括涡动相关系统,行星边界层塔,微波辐射计,风廓线仪和无线电探空系统观测的风温湿廓线及云雨雷达等)的紧迫性和具体方案,进而为研究青藏高原环境变化和山区灾害预测服务.

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.

The atmospheric wet pool:definition and comparison with the oceanic warm pool

海洋的温暖的水池(OWP ) 海运定义表面温度(SST ) 在海洋作为“热水库”被知道。在海洋的最温暖的部分反射事实有在空气的水蒸汽(WV ) 的最大的累积的最湿的区域，称为的大气的湿水池(AWP ) ，因为在 SST 和 WV 之间的著名 Clausius-Clapeyron 关系，应该被识别。在这研究，我们从 1988 年 1 月使用了 WV 和 SST 的 14 年的同时的观察到 2001 年 12 月定义 AWP 并且调查它与 OWP 联合和共变。AWP 和 OWP 的区域变化，矩心地点，和带的迁居的联合考试导致很多有趣的调查结果。结果能希望贡献我们特别地一般来说理解由空至海的相互作用和 El Niño/La Niña 事件的描述。

青藏高原降雨增加和气温升高对多年冻土水热动态贡献研究

在人类活动和全球气候变化驱动下,青藏高原气候整体呈现暖湿化变化趋势,由此引发的多年冻土活动层水热变化对寒区生态环境和寒区工程稳定性产生显著影响。目前,温度升高对多年冻土的影响机制较为明确,但降雨增加、降雨增加与气温升高共同作用下的多年冻土水热响应过程和机制尚不明确。在考虑雨水感热作用的地表能水平衡-冻土水热耦合模型的基础上,对比研究气温升高、降雨增加单一作用及其共同作用对活动层水热影响机制。结果表明:相比气温升高和降雨增加单一作用,暖湿化复合作用导致地表净辐射通量和蒸发潜热通量增长显著,地表感热降低更加明显,雨水感热影响较小,地表土壤热通量呈增加趋势;暖湿化复合作用下温度梯度液态水通量增长显著,基质势梯度液态水通量在浅层增幅也大于单独升温作用,但小于单一降雨增加作用,暖湿化导致暖季土壤含水率增幅小于单独降雨作用;暖湿化作用下活动层热传导通量在冷季增加显著且增幅小于单独升温作用,而液态水对流传热在暖季增加明显且增幅小于单独湿化作用;降雨增加促使土体暖季降温显著,暖湿化与单一气温升高均导致土体在冷季升温效果高于暖季;气温升高1.0℃引起多年冻土上限下移10cm,降雨增加100 mm促使上限抬升8 cm,暖湿化共同作用导致冻土上限下移6 cm;在暖湿化作用下,降雨增加对冻土降温作用较小,气温升高对冻土的升温效应仍占据主导。

Environmental factors controlling soil warming and wetting during 2000-2020 in permafrost and non-permafrost regions across the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau(QTP)has experienced rapid environmental changes,including climate warming and wetting,since the 1980s.These environmental changes significantly impact the shallow soil hydrothermal conditions,which have key roles in land-atmosphere feedback and ecosystem functions.However,the spatial variations and responses of soil hydrothermal conditions to environmental changes over the QTP with permafrost(PF)and seasonal frost(SF)remain unclear.In this study,we investigated the spatial variations in soil temperature(ST)and soil moisture(SM)changes over the QTP from 2000 to 2020 using 99 in-situ sites with observations at 4 depths(i.e.10,40,100 and 200 cm).The main environmental controlling factors were further identified using a calibrated statistical model.Results showed that significant(p<0.05)soil warming occurred at multiple soil layers during 2000-2020 with a wide variation(i.e.0.033-0.039℃ per year on average),whereas the warming rates at PF sites were two times greater than those at SF sites.In addition,the soil wetting rate was high over the SF region,whereas the soil wetting rate was low over the PF region.Aside from air temperature,changes in thawing degree days and solar radiation(Srad)contributed most to soil warming in the PF region,whereas changes in rainfall,Srad and evaporation(EVA)have been identified as the key factors in the SF region.As for soil wetting,changes in snowfall,freezing degree days and vegetation have noticeable nonlinear effects over the PF region,whereas changes in EVA,Srad and rainfall highlighted distinct linear and nonlinear effects in the SF region.These findings enhance our understanding of the hydrothermal impacts of future environmental changes over the QTP.

西北地区气候暖湿化增强东扩特征及其形成机制与重要环境影响

西北地区地处欧亚大陆腹地,水汽来源匮乏,干旱是其主要气候特征。近年来随着区域降水的不断增加,中国西北暖湿化问题引起国际及国内相关领域科学家和社会各界的广泛关注。为了揭示中国西北气候暖湿化增强东扩特征与形成机制及其重要环境效应,科学回应社会关切,研究团队利用多源融合数据,从多尺度、多维度对中国西北暖湿化问题开展全面深入研究,发现了西北湿化趋势具有显著的非线性增强特征,且湿化正在向东扩展,本世纪内西北仍维持暖湿趋势,明确了西北陆面蒸散对气候变暖具有特殊的负反馈机制,揭示了西北湿化趋势受多因子综合驱动机制;评估了西北暖湿化对区域生态环境、水资源、农业生产和粮食安全的重要影响及其互馈效应;提出了应对西北暖湿化的技术对策,形成了“西北地区气候暖湿化增强东扩特征及其形成机制与重要环境影响”系列研究成果。基于研究的重大决策咨询报告为新时代西部大开发和黄河流域生态保护和高质量发展等国家战略发挥了重要决策支撑,成果也受到国际学界广泛关注,并入选2022年度“中国生态环境十大科技进展”。

一场突发性局地大暴雨触发作用的分析和探讨

利用多种非常规高时空分辨率观测资料并结合ERA5(ECMWF Reanalysis V5)再分析资料,分析了2019年6月2日长春市区的一场突发性局地大暴雨的中尺度特征,结果发现,低层或高层冷中心、暖湿气流和冷池出流三者之间不同的相互作用是该过程两段不同强度降水产生的根本原因:第一时段降水较强,并伴有强雷电和冰雹,700 hPa附近较弱冷中心在低层偏南风急流作用下北移至长春站北部并叠加在高层强冷中心之下,其下沉气流在边界层顶附近受该处降水形成的冷池和冷锋后部冷平流阻挡向南回流,冷池出流强度增强并在长春站附近迫使强暖湿气流抬升,长春站上空层结不稳定性加强,当上游对流云团东移至该地时强烈发展,回波强度超过60 dBZ,后向传播作用形成东西向线状对流,列车效应显著;第二时段降水相对较弱,仅伴有雷电,长春上空中低层仍为暖平流控制,高层冷空气继续加强并南压,其下沉气流在边界层顶附近受低层急流作用向北辐散,冷平流较强并与第一阶段强降水产生的冷池出流(较弱冷平流)在长春站附近辐合,迫使其低层相对较暖的气团抬升,700 hPa以下转为垂直上升运动,对流云团移至该处再次发展并与周围对流云团合并形成线状对流群,但两支辐合气流均为冷平流,近地面层缺少热力条件配合,不利于上升气流加强和维持,强度不超过55 dBZ且质心较低,维持时间短。

日尺度下水热因子变化对青藏高原高寒草原生产力的影响特征

温度和降水变化显著影响高寒生态系统植被生长和系统功能。草地生产力作为草地系统功能强弱的重要体现,对气候变化,特别是温度和降水变化十分敏感。探究高寒草原生产力如何响应气候变化,对预测未来气候变化情景下高寒草地系统功能变化意义重大。前期研究大都从年或季节尺度探究气候变化对草地生产力的影响特征,缺乏更精细时间尺度的关联分析。本研究基于1997—2020年青藏高原高寒草原长期植被观测数据及相应气候资料,应用简单线性回归及偏最小二乘回归法(Partial Least Squares regression,PLS)探究了研究区草地地上净初级生产力对日尺度温度和降水变化响应特征。结果表明:(1)近24 a来研究区年平均气温和降水量分别以0.03℃/a和4.36 mm/a的速率显著升高;(2)近24 a来研究区草地生产力显著升高(增幅为5.24 g m^(-2)a^(-1)),且与年平均温度和降水量呈显著正相关关系;(3)日尺度分析表明,不同阶段温度和降水变化对草地生产力的影响不同,其中5—8月和9—10月的温度及5—7月和9—11月的降水是影响研究区草地生产力的气候因子关键作用期,尤以生长季温度(5—8月)和降水(5—7月)变化影响更高,这表明生长季气候变化是该高寒草地生产力变化的主要驱动因素。总之,本研究指出近24 a生长季温度和降水量显著增加对高寒草原生产力具有重要促进作用,这意味着青藏高原暖湿化对高寒草原生态系统功能(草地生产力)影响不仅依赖于温度和降水变化的幅度,同时亦与温度和降水变化的方向和是否同步密切相关。

近50年广东春运期间气温和降水协同变化的气候特征

根据近50年(1971—2020年)广东省86个气象站的观测数据、NCEP/NCAR再分析数据和NOAA海温数据,采用线性趋势分析、合成分析等统计方法,研究了广东春运期间气温和降水的时空分布特征,从气温降水协同变化的角度切入划分了气候异常类型,并对比分析了其异常成因。结果表明:近50年来,广东省春运期间平均气温呈现显著上升趋势,珠江三角洲和粤东地区最明显。而降水日数则表现出显著减少趋势,粤西北、粤东和粤西沿海最明显。气温和降水协同变化的异常年(冷湿(4年)、冷干(6年)和暖干(11年))共有21年,占全部年份的42%。冷湿年和冷干年,欧亚大陆中高纬度都表现出经向环流特征,西伯利亚高压偏强,有利于冷空气活跃南下。不同的是冷湿年东亚西部地区“北高南低”,低纬度地区“东高西低”,对应的冷空气路径为中、西路,有利于水汽输送;而冷干年东亚东部地区“北高南低”,低纬度地区一致偏低,对应的冷空气路径偏东,不利于水汽输送。另外,冷湿年前期赤道中东太平洋偏暖,呈现ElNiño状态,受其影响西太平洋副热带高压偏大偏强,西太暖池偏冷,在菲律宾海区域激发出一个反气旋性环流,有利于西南水汽输送到广东地区,降水偏多;而冷干年则相反。暖干年,东亚中高纬表现出“北低南高”的纬向环流分布,东亚大槽和西伯利亚高压偏弱,不利于冷空气的生成和南下,广东上空受反气旋式环流控制,辐散下沉,温高雨少。

气候变化背景下全球陆地干湿变化研究综述

气候变化背景下,全球水循环加剧,出现了大气变干与植被变绿等陆地干湿变化趋势的解耦现象,旱区面积变化也存在争议。为回答上述问题,在梳理常见干湿指标变化趋势与驱动因素的基础上,根据指标变化方向对其进行归类,然后从机理角度解析影响不同指标趋势耦合或解耦的关键要素,并提出未来干湿变化研究展望。结果表明,气候变化背景下,饱和水汽压差、干燥度指数和土壤水分指标显著变干,植被绿度和生产力显著变湿(增加),降水、径流、陆地水储量和其他复合指标区域分异明显、但整体趋势不显著。二氧化碳浓度增加、气温升高和土地利用变化是导致不同指标趋势分异的重要因素,不同指标的趋势分异也解释了旱区面积评估在不同维度上的差异。未来研究中应开展干湿变化的综合评估,其综合性主要体现在以下四个方面:1)关注大气-生态-水文多维度评估;2)解析自然与人类双重压力下,不同维度要素间的关联、互馈过程,及其对系统干湿演变的促进、限制与调节作用;3)重视干湿演变程中的极端灾害事件和空间上以旱区为代表的气候变化敏感性区域;4)构建以脆弱性评估与适应性治理为核心的气候变化应对路径。

西北气候暖湿化的农业经济影响评估:以宁夏为例

以宁夏农业经济为研究对象,综合气候学与经济学交叉学科理论,在阐述气候变化影响农业经济基本理论的基础上,基于微观计量经济学方法定量评估了1991—2020年历史气候变化和极端天气气候事件对宁夏农业经济产值的差异化影响,进而预估了SSP3-RCP8.5和SSP2-RCP6.0情景下2041—2070年和2071—2100年气候暖湿化的潜在影响。结果表明,平均气温和降水均非线性影响农业经济产值,极端天气气候事件显著抑制农业经济增长,极端高温与重旱未能形成“热旱”复合型灾害影响;SSP2-RCP6.0发展路径可以大幅减缓SSP3-RCP8.5路径下未来升温的潜在负面影响。评估结果揭示了西北气候暖湿化对农业经济的复杂影响,有助于为区域最佳适应气候变化提供科学依据。

Discussion of the“warming and wetting”trend and its future variation in the drylands of Northwest China under global warming

Since Shi et al.proposed that the climate in the drylands of Northwest China experienced a significant transition from a“warming and drying”trend to a“warming and wetting”trend in the 1980s,researchers have conducted numerous studies on the variations in precipitation and humidity in the region and even in arid Central Asia.In particular,the process of the“warming and wetting”trend by using obtained measurement data received much attention.However,there remain uncertainties about whether the“warming and wetting”trend has paused and what its future variations may be.In this study,we examined the spatiotemporal variations in temperature,precipitation,the aridity index(AI),vegetation,and runoff during 1950-2019.The results showed that the climate in the drylands of Northwest China and the northern Tibetan Plateau is persistently warming and wetting since the 1980s,with an acceleration since the 1990s.The precipitation/humidity variations in North China,which are mainly influenced by summer monsoon,are generally opposite to those in the drylands of Northwest China.This reverse change is mainly controlled by an anomalous anticyclone over Mongolia,which leads to an anomalous easterly wind,reduced water vapor output,and increased precipitation in the drylands of Northwest China.While it also causes an anomalous descending motion,increased water vapor divergence,and decreased precipitation in North China.Precipitation is the primary controlling factor of humidity,which ultimately forms the spatiotemporal pattern of the“westerlies-dominated climatic regime”of antiphase precipitation/humidity variations between the drylands of Northwest China and monsoonal region of North China.The primary reasons behind the debate of the“warming and wetting”trend in Northwest China were due to the use of different time series lengths,regional ranges,and humidity indices in previous analyses.Since the EC-Earth3 has a good performance for simulating precipitation and humidity in Northwest and North China.By using its simulated results,we found a wetting trend in the drylands of Northwest China under low emission scenarios,but the climate will gradually transition to a“warming and drying”trend as emissions increase.This study suggests that moderate warming can be beneficial for improving the ecological environment in the drylands of Northwest China,while precipitation and humidity in monsoon-dominated North China will persistently increase under scenarios of increased emissions.

吸入性损伤的诊断原则与治疗策略

吸入性损伤是危重烧伤患者死亡的重要原因之一,合并吸入性损伤的危重烧伤患者死亡率大大增加。既往在吸入性损伤的诊断和治疗上已经积累了丰富的临床经验,但是对于一些新的循证学证据及诊疗措施的认识仍十分有限。本文以笔者团队多年临床救治经验为基础,讨论了新的诊断原则(联合、全面、动态、专科诊断)、气道损伤深度分级理论与新的治疗策略[如常压高浓度氧疗、温-湿型呼吸过滤器及高流量呼吸湿化治疗仪湿化气道、护理方式、体外膜肺氧合(ECMO)支持等],总结了针对吸入性损伤诊断和治疗的新的综合方案以及循证学证据。吸入性损伤的救治是多方面、多学科的综合诊疗,深入探讨诊疗的新原则与新策略对于提高救治水平具有重要的临床意义。

青藏高原暖湿复合事件时空变化特征及其对生态环境质量的影响

在全球气候变暖背景下,青藏高原地区经历了显著的暖湿化,了解该区域暖、湿及暖湿复合事件对生态环境质量的影响具有重要的现实意义。本文选取1961—2019年青藏高原134个气象站观测数据,利用百分位阈值、遥感生态指数和相关分析等方法,研究了该地区近60 a暖事件、湿事件和暖湿复合事件的时空变化以及与生态环境质量的关系。结果表明:(1)1961—2019年青藏高原暖事件总体表现出“上升—下降—上升”的波动趋势,而湿事件、暖湿复合事件总体呈极显著的上升趋势。从空间分布看,暖事件在南部发生频次较高,湿事件在东部和南部发生频次较高,而暖湿复合事件在东北部发生频次较高。从时间变化看,暖事件、暖湿复合事件在南部呈减少趋势而在北部呈增多趋势,湿事件在整个高原范围内总体呈增加趋势。(2)青藏高原生态环境质量呈显著的“东南高而西北低”的空间格局,北部和西部显著改善而西北部有退化趋势。(3)青藏高原暖事件、湿事件和暖湿复合事件与当地生态环境质量总体表现为正相关,其中南部呈较明显的负相关关系,而中部和北部均呈显著的正相关关系。(4)暖、湿及暖湿复合事件对生态环境的影响具有高度的海拔依赖性,这三者与生态环境质量在中海拔地区(2500~4000 m)均表现为显著的正相关关系。

气候暖湿化及其对陇东冬小麦生产的影响

运用甘肃省西峰农业气象试验站1981—2019年冬小麦试验观测及同步气象观测资料,分析了39年气候暖湿化趋势及对陇东冬小麦生产的影响。结果表明,1981—2019年陇东年平均气温以0.0644℃/a趋势持续升高,春季气温升高最明显,冬季次之。1995年以来,陇东年平均气温和年降水量均呈显著增加趋势,暖湿化特征明显。暖湿化对陇东冬小麦生产产生了比较显著的影响:(1)播种期推迟,成熟期提前,全生育期和越冬期缩短,但生长季生长天数并没有明显缩短。(2)营养生长阶段显著缩短,生殖生长阶段显著延长,对产量形成十分有利。(3)水分利用率,产量、千粒重、籽粒数、主要发育期干物重等产量构成要素增加趋势明显,不孕小穗率、越冬死亡率等显著降低,尤其1995年以来,气候产量增加趋势明显。(4)气候暖湿化有效降低了干旱和晚霜冻危害,使冬小麦种植边界北扩,高产适生品种增加。

中药披肩联合温针灸在治疗风寒湿型肩周炎患者中的应用

目的探讨中药披肩联合温针灸治疗风寒湿型肩周炎的效果。方法选取2021年9月-2022年9月就诊于郑州中医骨伤病医院的60例风寒湿型肩周炎患者,将其随机分为对照组与试验组,各30例。对照组采取温针灸治疗,试验组采用中药披肩联合温针灸治疗,2组均治疗2周,比较2组肩部疼痛情况、肩关节功能评分及临床疗效。结果治疗后,试验组临床疗效好于对照组(Z=-2.045,P=0.041),疼痛评分低于对照组(t=4.892,P<0.001),肩关节功能评分高于对照组(t=-4.531,P<0.001)。结论中药披肩联合温针灸能有效缓解风寒湿型肩周炎患者疼痛症状,并能明显改善肩关节功能,值得临床推广。

李青教授“从饮治汗”临证经验

汗证是临床上常见病症,历代医家多以阴阳分治为总的治则治法。李青教授认为汗证病因多属人体气化功能失常所致,且汗证同饮证共属津液病范畴,脾虚则饮停,饮停则气滞,故提出“从饮治汗”兼顾机体气化功能的辨证思维。强调脾虚湿困类汗证,可从化饮以治汗,气行则饮行的思路入手。遵燥湿健脾,温阳化气的原则施治,临床疗效尤甚,期以此拓展临床治疗汗证新思路。

中国西北气候由暖干向暖湿转型的特征和趋势探讨

由于全球显著变暖和水循环加快 ,使得中国西北主要是新疆地区于 1 987年气候发生突然变化 ,随着温度上升 ,降水量、冰川消融量和径流量连续多年增加 ,内陆湖泊水位显著上升 ,洪水灾害也迅猛增加 ,同时 ,植被有所改善 ,沙尘暴日数锐减 ,从而改变了 1 9世纪末期至 2 0世纪 70年代的变暖变干趋势。以降水量增加超过蒸发量增加所导致的径流量增长及湖泊水位上升作为气候向暖湿转型的主要标准 ,西北地区目前的气候变化可分为 3个区域 ,即 1 )显著转型区 ;2 )轻度转型区 ;3)未转型区。作者初步认为 ,西北气候向暖湿转型可能是世纪性的 ,预期西北东部在 2 1世纪上半期也会向暖湿转变 ,但预测有较大的不确定性。