摘要
选取强E1 Nino年（1997／1998年）和强La Nina年（1998／1999年）作为个例，利用中国国家气候中心水平分辨率为60km的区域气候模式（RegCM—NCC）对东亚冬季风进行了数值模拟，结果表明：模式不仅从500hPa东亚大槽、副热带高压、地面蒙古冷高压和850hPa东亚风场等方面，模拟出两年冬季风系统的不同特征，而且也模拟出与ENSO事件密切联系的大气低层环流的明显差别，表明区域气候模式对ENSO暖、冷事件下东亚冬季风的差异有较好的模拟能力。数值模拟也能够再现中国南海、菲律宾群岛以东的西太平洋和盂加拉湾3个主要的冷涌区，以及在两年不同海温和环流背景下冷涌发生的频数变化。分析还表明，模拟结果能较好地反映两年冬季中国气温的空间分布特征，模拟出的冷空气过程、最冷时段出现时间与实际基本相符，模拟的主要降水带位置也与实况接近，特别是能够较好地模拟出中国南方地区1997／1998（1998／1999）年冬季异常多（少）的降水量。虽然数值模式的总体性能是较为满意的，但也发现在形势场的模拟中存在1998／1999年冬季东亚大槽模拟偏深和东亚沿海海平面气压梯度偏大等不足，需进一步加强对模式物理过程的研究。
Taking the strong E1 Nino episode in the winter of 1997/1998 and strong La Nina episode of 1998/1999 as typical cases, the work conducts numerical simulations of the East Asian winter monsoon using the regional climate model （RegCM-NCC） of the National Climate Center of China, which has 16 vertical levels, a 60 km horizontal resolution and a domain size of 151×99 grid points. The initial atmospheric conditions and lateral boundary data are from the NCEP/NCAR Reanalysis dataset. Lateral boundary conditions are provided every 12 hour via a relaxation method. The weekly optimum interpolations Ol SST. v2 data are linearly interpolated into daily values.
The model was initialized on November 1 and integrated up to the end of February for the two winters. Impacts of ENSO events on the East Asian winter monsoon are investigated by analyzing the differences of the winter meteorological fields between 1998/1999 and 1997/1998. Results show that the model not only reproduces well differences of East Asian winter monsoons in the two winters, especially in the main features related to 500 hPa East Asian trough, subtropical high, surface cold high over Mongolia and 850 hPa wind field, but also reveals the features of low level circulation that are believed to be closely related to ENSO events. The simulations can also capture the variation of cold surge genesis in the different background of SST and atmospheric circulation in the two seasons, as well as the three high frequency regions of cold surge occurrence over the South China Sea, the western Pacific Ocean east to Philippines and the Bay of Bengal. It＇s implied that the RegCMNCC has certain capability in the simulations of the impacts of ENSO events on East Asian winter circulations.
Moreover, the comparisons of some climate fields between observation and simulation reveal that the simulation gives realistic spatial distribution of seasonal averaged air temperature, the periods linked with cold waves, the position of the rain belt and the extremely abundant �
出处
《气象学报》
CAS
CSCD
北大核心
2007年第1期18-28,共11页
Acta Meteorologica Sinica
基金
国家"十五"科技攻关项目"全球与中国气候变化的监测和预测(2001BA611B-01)"
关键词
冬季风
ENSO事件
区域气候模式
数值模拟.
Winter monsoon, ENSO events, Regional climate model, Numerical simulation.
