三江平原湿地大面积开垦前后区域夏季气候状况的对比研究

Comparison of Summer Climate Conditions before and after Large Area Wetland Reclamation in the Sanjiang Plain

为了对比湿地大面积开垦前、后三江平原夏季气候状况差异和更加全面认识三江平原区域夏季气候特征,完善以往相关研究中因三江平原气象站点少而带来的研究结果的局限性,在10km分辨率下采用区域气候模式RegCM3,针对三江平原夏季水热同季的气候特点,以6月和7月为例,对20世纪50年代和90年代的夏季气候特征进行了数值模拟。结果表明:20世纪50年代,6月平均气温等值线总体上沿纬线分布,7月,山区的气温分布与6月相似,但平原区的气温分布基本沿经线分布;在20世纪90年代,6月的气温分布与50年代7月的气温分布很相似,7月的气温分布与90年代6月基本一致,只是平原区的气温经向梯度明显减小;总体上,研究区夏季降水量的分布在两个年代基本一致;与气温和降水量的观测数据相比,模拟结果更全面的反映了三江平原湿地大面积开垦前、后两个年代夏季气温和降水量的分布特征,修正了以往因气象站点少而产生的区域气候认识上的偏差。通过分析湿地大面积开垦前、后两个年代研究区夏季气候状况的差异,发现在湿地开垦强度最大的地区,气温和降水量的分布及其量值变化也最为明显。

The Sanjiang Plain had been one of the regions where the distribution of wetland was most centralized. Large area wetlands were reclaimed to crop through the large-scale exploitations in the last 50 years in the 20＇h century, and the situations of the underlying surface in the Sanjiang Plain were changed obviously. It was found that the large - scale reclamation were probably direct reasons that resulted in climate jumps of the Sanjiang Plain base on the 45 years observation datum of the weather stations in the Sanjiang Plain. Aiming at the climate characteristics of the Sanjiang Plain and taking example for the June and July, the summer climate of the Sanjiang Plain in 1950＇ s and 1990＇ s were simulated by using regional climate model RegCM3 at 10 km resolution in order to compare the differences of summer climate in the Sanjiang Plain for - and - aft large area wetland reclamation and to understand the climate characteristics of the Sanjiang Plain more comprehensive, conquer the disadvantages that weather stations distributed sparsely in other studies before. About the choice of the underlying surface types in the model, in 1950＇ s, the underlying surface types in the Sanjiang Plain was from the interpretation datum of the relief map in 1954, the underlying surface types in the other areas was from GLCC database, the underlying surface of the Sanjiang Plain were wetland and forest land primary ; in 1990＇ s, the underlying surface types in the Sanjiang Plain was from the interpretation datum of the TM remote sensing images in 1995, the underlying surface types in the other areas was from GLCC database, the underlying surface of the Sanjiang Plain was crop primary. The center of the simulations located at the 46°N, 132°E. The numbers of grid point in longitudinal direction were 107, and the numbers of grid point in latitudinal direction were 97. The time step in the simulations was 30 second. The results showed that, in 1950＇ s, temperature isoline was latitudinal at June, the temperature distribution of mountainous area at July was similar to that in June, but the temperature distribution of plain area was longitudinal; in 1990＇ s, the June temperature distribution was similar to the July temperature distribution in 1950＇s, the July temperature distribution was similar to the June temperature distribution, just the longitudinal grads minished obviously; as a whole, the precipitation distribution was consistent by and large in the two decades; compared with the observation datum, the simulation results reflected the summer temperature and precipitation distributions in the two decades before and after large area wetland reclamation more comprehensive, and revised the deficiencies to the regional climate which caused by the lack of weather stations. The climate differences in was found that the temperature most intensively the two decades before and after large area wetland reclamation and precipitation changed most evidently where the underlying were analyzed, it surface changed