Numerical Experiments on the Impact of Spring North Pacific SSTA on NPO and Unusually Cool Summers in Northeast China

A set of numerical experiments designed to analyze the oceanic forcing in spring show that the combined forcing of cold （warm） El Ni（n）o （La Ni（n）a） phases in the Ni（n）o4 region and sea surface temperature anomalies （SSTA） in the westerly drifts region would result in abnormally enhanced NorthEast Cold Vortex （NECV） activities in early summer.In spring,the central equatorial Pacific El Ni（n）o phase and westerly drift SSTA forcing would lead to the retreat of non-adiabatic waves,inducing elliptic low-frequency anomalies of tropical air flows.This would enhance the anomalous cyclone-anticyclonecyclone-anticyclone low-frequency wave train that propagates from the tropics to the extratropics and further to the mid-high latitudes,constituting a major physical mechanism that contributes to the early summer circulation anomalies in the subtropics and in the North Pacific mid-high latitudes.The central equatorial Pacific La Ni（n）a forcing in the spring would,on the one hand,induce teleconnection anomalies of high pressure from the Sea of Okhotsk to the Sea of Japan in early summer,and on the other hand indirectly trigger a positive low-frequency East Asia-Pacific teleconnection （EAP） wave train in the lower troposphere.

A Cool Place in Summer

The sweltering heat of last summer in Beijing made people feel as if they were living in a stuffy and smothering furnace. Many people packed up and escaped to such summer resorts as Yantai and Beidaihe. One day. A friend of mine in Zhangjiakou sent me a message inviting me to relax for a couple of days at Bashang in the summer. Bashang, as a unique cool

Thermal performance and comfort assessment of U-shape and helical shape earth-air heat exchanger in India

Earth Air Tunnel Heat Exchanger(EATHE)systems are not so much popular in India because of restricted acces-sibility of ground space in majority of residential and commercial sector.In the present article,thermal perfor-mance of newly designed helical shaped EATHE system has been compared with conventional U-shaped EATHE system by keeping similar geometrical and operational configuration for the summer(April-June)and winter(December-February),respectively.In this regard,therefore,numerical model of both EATHE systems have been designed and experimentally validated.The thermal performance of both EATHE systems has been compared in terms of outlet air temperature and effectiveness.The present numerical study suggested that the newly designed helical EATHE system exhibits better thermal performance with lower ground requirement as compared to con-ventional U-shaped EATHE system.To evaluate the thermal comfort potential of EATHE system in office buildings of India,composite climate specific adaptive thermal comfort boundaries has been used.The detailed thermal performance behaviour of the EATHE system suggests that an additional 80%of the time;ambient air condi-tions became thermally comfortable during peak summer season.In addition,analysis of the results revealed that EATHE system has more potential during heating operation mode to maintain indoor comfort in winter season of composite climate in India.

INFLUENCE OF EL NINO ON WEATHER AND CLIMATE IN CHINA

El Nino as well as the Southern Oscillation is one of the strongest signals known so far over climatic noise in interannual variations of the atmosphere and oceans.A great number of studies have shown definitely relationships be- tween the events and climatic anomalies in China.In this review,observational results obtained in the recent several years are first summarized.Then the possible physical mechanisms on the influence of El Nino are presented and,finally, the associated problems are discussed.