1998年南海、孟加拉湾夏季风期间动能收支特征
KINETIC ENERGY BUDGET OF SUMMER MONSOON OVER SOUTH CHINA SEA AND THE BAY OF BENGAL IN 1998
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摘要: 该文采用1998年加密观测资料经同化处理后得到的客观分析格点资料, 对南海地区和孟加拉湾地区的动能收支进行了诊断分析和对比, 得出: B区夏季风爆发, 其850 hPa区域平均总动能表现为爆发性增长, C区则表现为一个逐步增长的过程.越赤道气流通过南边界的动能输送对B区夏季风建立贡献很大, 西边界动能输入对C区夏季风建立也起了十分显著的作用.季风盛行期, B区夏季风动能的发展维持主要是动能水平通量散度的贡献, 其中西边界动能的流入贡献最大, 孟加拉湾夏季风的变化主要为印度季风影响所致; C区夏季风动能主要是依靠其区域内动能制造来维持.对于850 hPa层, B区主要通过斜压过程制造动能, 正压过程破坏更多的动能, C区主要是正压过程制造动能.两区对流层高层都为动能主要流出区, 而对流层低层, B区为动能流入区, C区为动能流出区.Abstract: With the assimilation data of the IOP period of South China Sea Monsoon Experiment, the comparison and study of mechanisms responsible for the generation, evolution laws and maintenance of kinetic energy in the South China Sea (Region C) and the Bay of Bengal (Region B) are made. The analysis shows that mean kinetic energy of the general flow in Region B grows explosively and the kinetic energy increases gradually with amplitude smaller than that in Region B when monsoon breaks out. The transport of kinetic energy in the cross-equatorial flow is important for the establishment of southwest monsoon in Region B. The kinetic energy flowing into the west boundary in Region C is also significant for the establishment of monsoon there. During the prevalence of monsoon, the evolution and variation of kinetic energy in southwest monsoon in Region B mainly depend on the contribution of divergence of horizontal flux while the kinetic-energy generating terms within Region C play the maximum role. For the 850 hPa layer, however, the baro clinic generation of kinetic energy plays a dominant role in Region B but more kinetic energy is reduced by the baro tropic process; energy is produced baro trocally in Region C. In the upper layers of the troposphere in both regions can be found the outflow of kinetic energy, but in the lower layers inflow of energy can be found in Region B and outflow of energy be found in Region C.
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Key words:
- Kinetic energy diagnoses;
- Summer monsoon;
- SCS;
- The Bay of Bengal
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表 1 1998年夏季风盛行期B区和C区各层平均动能制造项和动能水平通量散度项的值
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