Climate changes in Guangdong are studied based on temperature data of 86 meteorological stations in Guangdong Province during 1961 – 2000, temperature data in Guangzhou during 1908 – 2002, and sea level data in the South China Sea during 1958 – 2001. Significant climate warming and sea level rise in Guangdong is demonstrated. Possible influences of climate warming on agriculture in Guangdong are discussed in terms of thermal resources, crop and breed layout, crop yield, diseases, insect pests and weeds as well as agrometeorological disasters, etc. In the final part, agricultural strategies of mitigating and adapting to the climate changes are given.
Based on daily NCEP reanalysis data, OLR and satellite rainfall data, the characteristic of theactivities of South China Sea summer monsoon(SCSSM) in 2004 were analyzed. The results showed that theestablishment of SCSSM was little later than normal and the intensity was stronger than normal. Influenced bythe location of the northwest Pacific subtropical high, which was much northward and westward than normal,SCSSM was active mainly in the South China Sea areas. There existed obvious intraseasonal oscillation and twosignificant periods of SCSSM, one was about 20-30 days and the other about 40-50 days. The transportation ofmoisture was concentrated on the South China Sea and the northwest Pacific regions, reducing the northwardtransportation and resulting in drought in southern China.
Interdecadal variability characteristics of ocean-atmosphere interaction in the tropical areas are investigated by using atmospheric reanalysis data and oceanic dataset. Results indicate that due to the ocean-atmosphere system’s internal adjustment on interdecadal time scales, the exchanges of latent heat and sensible heat between the ocean and at- mosphere are reduced by means of weakening trade wind, causing oceanic thermocline anomalies and resulting in unusual warming of sea surface tem- perature in the central and eastern Pacific. Mean- while the increases of sea surface temperature fa- cilitate much more development of convection in the eastern Pacific and excite a local ascending motion in the eastern and anomalous westerlies in the central and eastern Pacific, which further weaken the Walker circulation, and vice versa. Thus these processes constitute an interdecadal mode of positive feedback. This interdecadal feedback of the tropical ocean- atmosphere system is different from the previous conclusion of a so-called midlatitude-driving mecha- nism, which was used to explain the decadal vari- ability in the tropical Pacific Ocean.
LI ChunhuiWANG DongxiaoLIANG JianyinGU DejunLIU Yun
This paper is devoted to the features of sea-surface heat budget during the active/break phases of the 2000 summer monsoon in the South-China Sea (SCS) by means of the observed air-sea heat fluxes and data from Xisha Weather Station and NCEP/NCAR in the same period.Results suggest that the primary factors affecting sea-surface thermal budget are solar shortwave penetrating radiation and latent heat flux.Regardless of their changes,however,the thermal gain is reduced or becomes net loss at the active stage and the thermal gain gets gradually increased in the weakening and lull periods:during the first emergence of southwest monsoon the net loss happens thanks to the dramatic diminution of penetrating radiation resulting from increased cloudiness and intense precipitation:while at the re-emergence of the wind.reduced net sea-surface thermal gain is attributed to the sharp increase in latent heat flux resulting from intense evaporation:owing to great thermal inertia of water the SST change lags behind that of heat budget over the sea surface, and the lagging is responsible for regulating the budget by affecting latent heat fluxes,which,in turn.has effect upon the change of the SST,thereby forming short-term oscillations that are in association with the active/break phases of the monsoons.Part of the conclusions have been borne out by the observational study based on 1998 and 2002 data.
