2013—2017年夏季东北冷涡下东北地区MCS的统计特征

利用2013—2017年6—8月FY-2E和FY-2G地球静止卫星相当黑体温度（Black Body Temperature,TBB）资料、NCEP/NCAR再分析资料,对我国夏季东北冷涡下东北地区MCS的分布和活动特征进行了统计分析,结果表明：（1） MCS的活动具有明显的月际变化和日变化特征,6月对流活动最活跃。MCS的主要移向是东、东北和东南,平均移动距离3.99个经纬距。（2） MCS成熟时刻的面积、偏心率和生命史均小于江淮地区以及中国中东部,云顶高度低于江淮地区,整个生命史表现出发展快消亡慢的特征,与江淮地区相反。（3）基于MCS的定义得到的Z标准,对2016—2017年的MCS作了统计分析并与J标准统计得到的MCS进行对比,得出,两种定义下的MCS环境场特征基本一致,主要表现为MCS多生成于500 hPa槽前和槽后,对流层高层MCS位于双急流之间靠近北支急流的辐散区,南侧急流高度在200 hPa,北侧的急流高度在250 hPa。低层,位于低空急流左侧,低涡南侧、东南侧,有较强的水汽和动量输送。槽前生成的MCS南侧中层存在垂直反环流向MCS输送干暖空气与位涡,槽后生成的MCS两侧均有大值位涡向其输送,同时北侧冷干空气的输送使锋区及上升运动加强,更有利于MCS的形成。（4）两种标准下的MCS造成的降水明显不同,在统计强降水方面Z标准要优于J标准。由于Z标准空间与时间尺度较小,统计得到的MCS较多;但同时会遗漏部分相对弱的MCS。     

Evaluation of Agricultural Climatic Resource Utilization During Spring Maize Cultivation in Northeast China Under Climate Change

Agricultural climatic resources （such as light,temperature,and water） are environmental factors that affect crop productivity.Predicting the effects of climate change on agricultural climatic resource utilization can provide a theoretical basis for adapting agricultural practices and distributions of agricultural production.This study investigates these effects under the IPCC （Intergovernmental Panel on Climate Change） scenario A1B using daily data from the high-resolution RegCM3 （0.25° ×0.25°） during 1951-2100.Model outputs are adjusted using corrections derived from daily observational data taken at 101 meteorological stations in Northeast China between 1971 and 2000.Agricultural climatic suitability theory is used to assess demand for agricultural climatic resources in Northeast China during the cultivation of spring maize.Three indices,i.e.,an average resource suitability index （Isr）,an average efficacy suitability index （Ise）,and an average resource utilization index （K）,are defined to quantitatively evaluate the effects of climate change on climatic resource utilization between 1951 and 2100.These indices change significantly in both temporal and spatial dimensions in Northeast China under global warming.All three indices are projected to decrease in Liaoning Province from 1951 to 2100,with particularly sharp declines in Isr,Ise,and K after 2030,2021,and 2011,respectively.In Jilin and Heilongjiang provinces,Isr is projected to increase slightly after 2011,while Ise increases slightly and K decreases slightly after 2030.The spatial maxima of all three indices are projected to shift northeastward.Overall,warming of the climate in Northeast China is expected to negatively impact spring maize production,especially in Liaoning Province.Spring maize cultivation will likely need to shift northward and expand eastward to make efficient use of future agricultural climatic resources.     

我国东北地区降水空间分布及干湿驰豫时间的研究

根据东北地区24个典型测站1951—2001年的降水量资料,利用EOF方法分析了我国东北地区的降水空间分布;同时,通过子波诊断技术结合突变点数建模技术,研究了我国东北地区的降水演变周期特征,并对干湿态之间转换的驰豫时间做了定量的研究。结果表明：东北地区的降水空间分布具有整体一致的性质,同时还存在南北及东西的差异;大部分站点都具有干→湿的驰豫时间长于湿→干的驰豫时间的特征,体现了东北地区容易维持干旱状态的特性。     

发挥开发区先导作用 打造节约集约用地模范区——大连经济技术开发区创建国土资源节约集约模范县（市）的经验

大连经济技术开发区是1984年10月经国务院批准设立的首个国家级经济技术开发区,是我国东北地区改革开放的前沿和窗口,经过20多年的发展,已成为辽宁省乃至东北地区重要经济增长点。     

A Study on Water Vapor Transport and Budget of Heavy Rain in Northeast China

The characteristics of moisture transport and budget of widespread heavy rain and local heavy rain events in Northeast China are studied using the NCEP--NCAR reanalysis 6-hourly and daily data and daily precipitation data of 200 stations in Northeast China from 1961--2005. The results demonstrate that during periods with widespread heavy rain in Northeast China, the Asian monsoon is very active and the monsoonal northward moisture transport is strengthened significantly. The widespread heavy rainfall obtains enhanced water vapor supply from large regions where the water vapor mainly originates from the Asian monsoon areas, which include the East Asian subtropical monsoon area, the South China Sea, and the southeast and southwest tropical monsoon regions. There are several branches of monsoonal moisture current converging on East China and its coastal areas, where they are strengthened and then continue northward into Northeast China. Thus, the enhanced northward monsoonal moisture transport is the key to the widespread heavy rain in Northeast China. In contrast, local heavy rainfall in Northeast China derives water vapor from limited areas, transported by the westerlies. Local evaporation also plays an important role in the water vapor supply and local recycling process of moisture. In short, the widespread heavy rains of Northeast China are mainly caused by water vapor advection brought by the Asian monsoon, whereas local heavy rainfall is mainly caused by the convergence of the westerly wind field.     

Observations of Cloud Condensation Nuclei in North China

Using a DMT （Droplet Measurement Technologies） continuous flow streamwise thermal gradient cloud condensation nuclei （CCN） counter mounted on a Cheyenne IIIA aircraft, about 20 flights for aircraft mea- surements of CCN over North China were conducted in the autumn of 2005 and spring of 2006. According to the design for aircraft observation, the method of spiral ascent or descent in the troposphere was used for the vertical measurement of CCN, and some certain levels were chosen for horizontal measurement. The vertical distributions of CCN concentrations show that most CCN particles are concentrated in the low level of troposphere and CCN concentration decreased with height increasing. It suggests that the main source of CCN is from the surface. This result is consistent with former studies during 1983-1985 in China with a static thermal gradient CCN counter. The comparison of vertical observations between polluted rural area near Shijiazhuang and non-polluted rural area near Zhangjiakou shows that there is about five times difference in CCN concentration. But over two polluted cities, Shijiazhuang and Handan, there is no notable difference in CCN concentration. The horizontal flight measurements for penetrating the cumulus clouds experiment show the apparent decrease of CCN in clouds. It confirms that cloud has a definite consumptive effect on CCN particles because some CCN particles can form cloud droplets. The surface measurements of CCN in Shijiazhuang City were made during June-August 2005. The statistical CCN data show the great difference in concentration at the same supersaturation （S） in Shijiazhuang summertime. The minimum CCN concentrations were 584, 808, and 2431 cm-3, and the maximum concentrations were 9495, 16332, and 21812 cm-3 at S=0.1%, 0.3%, and 0.5%, respectively. CCN has a diurnal variation cycle. From 0600 BT, the concentration began to increase and reached the maximum at about noon. Then it generally decreased throughout the afternoon. The reason maybe is related to the onset o     

Prediction Research of Climate Change Trends over North China in the Future 30 Years

A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 （Global Ocean-Atmosphere-Land system coupled model）, developed by the State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP）, Chinese Academy of Sciences （CAS）. In order to validate the model, the modern climate during 1951-2000 was first simulated by the GOALS model with the actual greenhouse gas concentration, and the simulation results were compared with observed data. The simulation results basically reproduce the lower temperature from the 1960s to mid-1970s and the warming from the 1980s for the globe and Northern Hemisphere, and better the important cold （1950 1976） and warm （1977-2000） periods in the past 50 years over North China. The correlation coefficient is 0.34 between simulations and observations （significant at a more than 0.05 confidence level）. The range of winter temperature departures for North China is between those for the eastern and western China＇s Mainland. Meanwhile, the summer precipitation trend turning around the 1980s is also successfully simulated. The climate change trends in the future 30 years were simulated with the CO2 concentration under IPCC SRES-B2 emission scenario. The results show that, in the future 30 years, winter temperature will keep a warming trend in North China and increase by about 2.5~C relative to climate mean （1960-1990）. Meanwhile, summer precipitation will obviously increase in North China and decrease in South China, displaying a south-deficit-north-excessive pattern of precipitation.     

Simulation of Precipitation in Monsoon Regions of China by CMIP3 Models

The output of 25 models used in the Coupled Model Intercomparison Project phase 3 （CMIP3） were evaluated, with a focus on summer precipitation in eastern China for the last 40 years of the 20th century. Most models failed to reproduce rainfall associated with the East Asian summer monsoon （EASM）, and hence the seasonal cycle in eastern China, but provided reasonable results in Southwest （SW） and Northeast China （NE）. The simulations produced reasonable results for the Yangtze-Huai （YH） Basin area, although the Meiyu phenomenon was underestimated in general. One typical regional phenomenon, a seasonal northward shift in the rain belt from early to late summer, was completely missed by most models. The long-term climate trends in rainfall over eastern China were largely underestimated, and the observed geographical pattern of rainfall changes was not reproduced by most models. Precipitation extremes were evaluated via parameters of fitted GEV （Generalized Ex- treme Values） distributions. The annual extremes were grossly underestimated in the monsoon-dominated YH and SW regions, but reasonable values were calculated for the North China （NC） and NE regions. These results suggest a general failure to capture the dynamics of the EASM in current coupled climate models. Nonetheless, models with higher resolution tend to reproduce larger decadal trends and annual extremes of precipitation in the regions studied.