东北地区降水偏多 华南局地暴雨成灾──1997年5月

东北地区降水偏多华南局地暴雨成灾—１９９７年５月—钱传海（中央气象台，北京１０００８１）５月，东北大部、华北北部、南疆大部及黄淮等地降水明显偏多，旱情缓解。西北地区东部、华北西部等地降水明显偏少，旱情持续或发展。南方大部地区降水接近常年或偏少，但华南...     

西北大部旱情加剧 江南局地暴雨成灾

西北大部旱情加剧江南局地暴雨成灾－１９９５年５月－徐良炎（北京国家气候中心，北京１０００８１）５月，东北大部、华北东部降水偏多，京、津、冀等地旱情缓解；西北大部、华北西部降水偏少，宁、甘、陕等地旱情加剧。南方雨水比较调匀，无大范围明显旱涝；江南局地暴...     

华北东北持续晴热高温 南方局部地区暴雨成灾──1997年6月

华北东北持续晴热高温南方局部地区暴雨成灾—１９９７年６月—张玲（中央气象台，北京１０００８１）６月份，我国北方大部地区降雨偏少，其中西北地区东部、华北大部及黄淮北部等地降雨很少，旱情日趋严重，东北平原大部也再度出现旱情。南方大部地区月降雨量基本接近常...     

北方麦区雨水不均 江南局地暴雨成灾

北方麦区雨水不均江南局地暴雨成灾－１９９５年５月－尹炳凡（北京中央气象台，北京１０００８１）本月，我国北方冬麦区降水不均，呈东多西少态势。东北大部和华北东部地区雨水丰沛，旱情有不同程度缓解；西北大部和华北西部地区降水稀少，有些地区发生了严重干旱．南方...     

北方降水少 麦区旱情重 南方雨雪多 华南遭冻害—1996年2月—

2月，全国大部地区降水偏少，其中北方冬麦区大部雨雪稀少，京、津、冀、晋、鲁等地旱情日趋严重，但陕、豫等地普降瑞雪，旱情缓解；江南、华南下半月持续低温阴雨（雪），苏、皖、闽等省大部旱情解除，但华南等地遭受严重冻害。月内，气温波动较大，上半月偏暖，下半月偏冷。月平均气温，东北大部及青海等地偏高，华南及西南部分地区偏低，全国其余大部地区基本接近常年。月日照时数，东北、华北、江南及华南中西部偏多，云南东部和南部偏少，全国其余大部基本接近常年。1北方冬麦区雨雪稀少，部分地区旱情严重2月，我国淮河以北地区雨雪…     

降雨增多大部旱情缓解 台风袭击闽苏损失较重—2000年8月—

8月份 ,东北大部、华北东部、黄淮东部、江南大部、华南东部、西南大部、西北大部降水量接近常年或偏多 ,北方及长江中下游的大部地区旱情得到缓解 ,湖北、陕西等省局部地区发生暴雨洪涝、泥石流等灾害 ;华北北部和中西部、华南西部及黄淮西部、西北地区的部分地区降水偏少 ,内蒙古、山西、安徽、广西等地的部分地区仍有不同程度的旱象。月平均气温除江南大部、四川盆地等地略偏低外 ,全国大部地区接近常年或偏高 ,其中东北地区大部和内蒙古东北部偏高 2～3℃。月内 ,有 3个台风袭击我国 ,福建、江苏等省损失较重。1　全国大部旱情缓解 ,部…     

陕晋终霜迟 台风登陆早

本月,全国大部气温接近常年同期,中旬陕西北部、山西、内蒙古、宁夏等地的大部分地区出现终霜冻。江南东部、华南东部及青海、西藏、云南等省区大部降水较多,局部地区出现洪涝。上旬末及下旬初,东北、华北大部普降喜雨,旱情得到不同程度缓解。     

冬麦区旱情缓解 江南异常多雨 冷空气袭击全国 华南异常偏暖

冬麦区旱情缓解江南异常多雨冷空气袭击全国华南异常偏暖－１９９７年１１月－陈峪（国家气候中心,北京１０００８１）１１月,黄淮、江淮、江南大部降水偏多,东北、华北北部、华南大部、西南大部降水偏少。中、下旬,北方冬麦区出现较大范围降水,大部旱情缓解,但河北...     

北方气温偏高麦区干旱南方阴雨连绵牧区雪灾—1997年12月—

北方气温偏高麦区干旱南方阴雨连绵牧区雪灾—１９９７年１２月—孙冷１２月份,降水量大致呈北少南多分布。东北大部、华北西部、西北大部降水明显偏少,晋、陕、甘、宁等省（区）的部分地区旱情持续;南方大部、华北东部、北疆北部、青海南部等地降水偏多,藏、青、新等...     

北方瑞雪纷飞小麦得益 南方低温阴雨作物受害1993年1月

本月上半月,北方喜降瑞雪,有利小麦安全越冬;南方出现连阴雨雪天气,作物生长和交通运输等受到影响。中下旬全国大部明显偏冷,南方部分作物遭受冻害。1 北方普降瑞雪,旱情明显缓解 本月,北方大部地区降水量普遍有2—10mm,其中冬麦区南部达10—50mm。与往年同期相比,华北大部、西北大部和黑龙江北部等地偏多3成—4倍,东北大部和内蒙、新疆、山东三省(区)大部以及河北东北部及东     

2001～2010年中国区域土地利用/覆盖变化对陆面过程影响的模拟研究

基于2001年和2010年中分辨率成像光谱仪MODIS（MODerate-resolution Imaging Spectroradiometer）土地覆盖数据,利用公共陆面模式（Community Land Model, CLM）模拟真实的土地利用/覆盖变化（Land Use/Cover Change, LUCC）对地表能量平衡和水分循环过程的影响。研究表明:1）在2001～2010年,中国LUCC最明显的区域位于干旱半干旱区过渡带、半干旱半湿润区过渡带和南方地区;中国区域荒漠减少0.92%,草地减少0.01%,农田增加0.77%,森林增加2.86%,植被覆盖度整体增加。2）在2001年和2010年两种土地利用/覆盖背景下,LUCC使大部分地区感热通量增加,植被蒸腾、蒸发潜热通量增加,土壤表面蒸发潜热通量减小。3）LUCC使大部分地区地表径流减小;中国西北东部、华北和东北地区土壤湿度减小,其他地区土壤湿度增加,仅干旱半干旱过渡带上的土壤湿度发生了显著变化。4）当典型过渡带区域由荒漠变为草地后,感热通量增加1.11 W m?2,潜热通量增加0.14 W m?2;冠层蒸腾和蒸发分别增加0.039 mm d?1、0.009 mm d?1。土壤湿度平均减小0.01 m3 m?3,且随深度增加变干更明显,这是由于根系吸收了较多深层土壤水分,以满足植被显著增加的蒸腾而产生的结果。当草地变为灌木时,其能量通量和水分循环的变化与上述结果类似。     

IMPACTS OF CLIMATE CHANGE ON CROPPING SYSTEM AND ITS IMPLICATION FOR AGRICULTURE IN CHINA

Based on the analyses on amplitudes of historical variation of temperature and precipitation inthe past 500 years and latest 100 years,according to the regional climate change scenarios forChina estimated by composite GCM,the potential impacts of climate change on cropping systemsin China in future are simulated and assessed using the cropping system model developmentspecially for the Chinese cropping patterns.It is shown that under the projected future climatechange by 2050 the most parts of the present double cropping area would be replaced by thedifferent triple cropping patterns while the current double cropping area would shift towards thecentral part of the present single cropping area.More explicitly,the northern boundary of triplecropping area would shift from its current border at the Changjing River to the Huanghe River,ashift of more than 5 degrees of latitude.And the shift of multiple cropping areas leads to asignificant decrease of single cropping area.Furthermore,considering the changes mentioned above in combination with the likely negativebalance of precipitation and evapotranspiration and,therefore,increase of moisture stress(i.e.less water availability),as well as the possible increase of heat stress disaster and decrease of LGS(length of growing season),the potential implication of climate change for agriculture in China arealso analyzed roughly in this paper.As a result,however,it is still very difficult to reach a specific conclusion that the futureclimate change will he favorable or unfavorable to farm in China because of the complicated Chinesefarming patterns,the complex-various social and economic environment of agriculturaldevelopment and,especially,a great scientific uncertainties in the investigation/prediction ofclimate change.     

Adaptation to a warming-drying trend through cropping system adjustment over three decades: A case study in the northern agro-pastural ecotone of China

Long-term field monitoring data and historical crop data are useful to assess the impacts of climate change and to manage cropping systems.The objectives of this study are to understand the cropping system response to a warming-drying trend in the northern agro-pastural ecotone(NAE)of China and to document how farmers can adapt to the warming-drying trend by changing cropping system structure and adjusting planting date.The results indicate that a significant warming-drying trend existed in the NAE from 1980 to 2009,and this trend significantly decreased crop(spring wheat,naked oat,and potato)yields.Furthermore,the yield decreased by 16.2%-28.4%with a 1℃increase in maximum temperature and decreased by 6.6%-11.8%with a 10%decrease in precipitation.Considering food security,water use efficiency,and water ecological adaptability in the semi-arid NAE,cropping system structure adjustment(e.g.,a shift from wheat to potato as the predominant crop)and planting date adaptation(e.g.,a delay in crop planting date)can offset the impact of the warming-drying trend in the NAE.Based on the successful offsetting of the impact of the warming-drying trend in the NAE,we conclude that farmers can reduce the negative effects of climate change and minimize the risk of crop failure by adapting their cropping system structure at the farming level.     

Responses of arid and semiarid watersheds to increasing carbon dioxide and climate change as shown by simulation studies

The atmospheric concentration of carbon dioxide is expected to double in the next century causing increased temperatures and decreasing precipitation in some regions of the U.S. The increase in CO₂ will also directly affect stomatal conductance of plants. At the first-order watershed scale, changes in evaporative demand, transpiration, and runoff will also occur. Previous modeling studies of the effect of increased CO₂ on the water budgets of watersheds have been single-factor exercises where a single parameter representing stomatal conductance was reduced and the results noted. After showing validation results of the hydrology module, we used a comprehensive ecosystem model to examine the consequences of changes in precipitation, temperature, and CO₂-induced plant-function characteristics on small-basin runoff. As a result of the complex interactions and of the compensatory mechanisms simulated by the model, we conclude that for arid and semiarid watersheds of the western United States, there will be little change or an actual decrease in surface runoff because of increased CO₂ and climate change. This is due to the decrease in precipitation imposed on the model simulations. Implementing stomatal closure in the model did not increase runoff from the watersheds when temperatures were increased and precipitation decreased.     

Changes in Components of the Water Balance in the Croatian Lowlands

Summary ?This paper deals with variations and trends in some components of the water balance: the soil water content; evaporation loss from the soil (from the surface and underlying layers); transpiration; ground water recharge and runoff. These components are calculated by means of the Palmer procedure. This analysis is based on data from Osijek, Croatia from this century (1900–1995). Besides the meteorological input parameters necessary for the water balance calculations, i.e. precipitation, temperature and relative humidity, the pedological characteristics of this area have also been taken into account. Fluctuations have been considered by means of the 11-year binomial filtered series and linear trends were tested by means of the Mann-Kendall rank test. For a closer look on the trends of water balance components, a progressive analysis of the time series was performed, too. The results show a significant increase in potential evapotranspiration and evapotranspiration and decrease in runoff and soil water content has occurred during the century. Received February 22, 1999/Revised August 3, 1999     

Assessment of climate change effects in Aegean river basins: the case of Gediz and Buyuk Menderes Basins

IPCC Fourth Assessment Report (AR4) discloses that the global climate system is undoubtedly warming. Observations have shown that many natural systems, including hydrologic systems and water resources, are being affected by regional climate changes, particularly temperature increases. Eventually, these effects will have to be considered in water resources planning and management. Accordingly, need is indicated to evaluate the impact of expected climate change on hydrology and water resources at regional and local levels. The presented paper summarizes the results of the sub-project studies under the United Nations Development Program-Global Environment Facility (UNDP-GEF) Project. The studies cover the generation of climate change scenarios, modeling of basin hydrology, and testing the sensitivity of runoff to changes in precipitation and temperature. Simulation results of the water budget model have shown that nearly 20% of the surface waters in the studied basins will be reduced by the year of 2030. By the years 2050 and 2100, this percentage will increase up to 35% and more than 50%, respectively. The decreasing surface water potential of the basins will cause serious water stress problems among water users, mainly being agricultural, domestic and industrial water users.     

Vulnerability and adaptation to climate variability and water stress in Uttarakhand State, India

This paper presents a participatory approach to investigate vulnerability and adaptive capacity to climate variability and water stress in the Lakhwar watershed in Uttarakhand State, India. Highly water stressed microwatersheds were identified by modelling surface runoff, soil moisture development, lateral runoff, and groundwater recharge. The modelling results were shared with communities in two villages, and timeline exercises were carried out to allow them to trace past developments that have impacted their lives and livelihoods, and stimulate discussion about future changes and possible adaptation interventions.     

Implementation of a surface runoff model with Horton and Dunne mechanisms into the regional climate model RegCM_NCC

A surface runoff parameterization scheme that dynamically represents both Horton and Dunne runoff generation mechanisms within a model grid cell together with a consideration of the subgrid-scaie soil heterogeneity, is implemented into the National Climate Center regional climate model （RegCM_NCC）. The effects of the modified surface runoff scheme on RegCMANCC performance are tested with an abnormal heavy rainfall process which occurred in summer 1998. Simulated results show that the model with the original surface runoff scheme （noted as CTL） basically captures the spatial pattern of precipitation, circulation and land surface variables, but generally overestimates rainfall compared to observations. The model with the new surface runoff scheme （noted as NRM） reasonably reproduces the distribution pattern of various variables and effectively diminishes the excessive precipitation in the CTL. The processes involved in the improvement of NRM-simulated rainfall may be as follows： with the new surface runoff scheme, simulated surface runoff is larger, soil moisture and evaporation （latent heat flux） are decreased, the available water into the atmosphere is decreased; correspondingly, the atmosphere is drier and rainfall is decreased through various processes. Therefore, the implementation of the new runoff scheme into the RegCMANCC has a significant effect on results at not only the land surface, but also the overlying atmosphere.     

基于CMADS驱动SWAT模型的富春江水库控制流域水量平衡模拟

以富春江水库控制流域为研究区域,利用中国大气同化驱动数据集（CMADS V1.1）驱动SWAT水文模型,对富春江水库控制流域进行了逐日径流模拟,探讨了流域2008-2016年径流变化及水量平衡过程。结果表明：CMADS V1.1数据集驱动SWAT模型对研究区域的径流变化具有较好的模拟效果,在验证期,逐日模拟的效率系数大于0.70,决定系数大于0.75,达到了模型评价标准。在流域水量平衡各项中,地表径流和蒸散发为主要的输出项,分别占降水量的57.2%和36.2%,其中蒸散发量年际变化较为平稳。降水量、地表径流量、土壤对地下水补给、地下侧流量、蒸散发量最大值均出现在6月,最小值均出现在1月。流域径流量以地表径流为主,其在各个月份与月降水变化趋势基本一致。而基流量较小,且各月基流量对降水量的响应并不显著。     

Sensitivity of a GCM simulation to subgrid infiltration and surface runoff

A subgrid parameterization of infiltration and surface runoff was evaluated using a land surface model coupled to an atmospheric general circulation model. Averaged over 5 year simulations, the subgrid parameterization resulted in significantly less infiltration of water into the soil compared to a simulation without subgrid hydrologic processes. As a result, the soils were drier, latent heat flux decreased, and surface air temperature increased. These results are consistent with other studies of subgrid hydrologic parameterizations, which also resulted in drier soils, decreased latent heat flux, and warmer surface temperatures. Several river basins were studied in detail. In the Amazon and Lena basins, the subgrid parameterization resulted in better annual runoff compared to observed annual river flow; surface air temperature was unchanged in the Amazon and better, compared to observations, in the Lena. In the Ob, Yenisey, and Amur basins, the subgrid parameterization resulted in too much annual runoff; July surface air temperature was unchanged or worse (Amur). Annual runoff for the Mississippi basin was better with the subgrid parameterization, but July surface air temperature was worse. These results suggest the utility of subgrid hydrologic parameterizations vary among river basins depending on the relative importance of Horton and Dunne runoff and the geologic factors affecting runoff generation.