Simulation And Projection Of Winter Agricultural Climatic Resources In The Scenario Of Climate Change Over Guangxi

Agricultural climate resources are directly involved in agricultural production with light, temperature, humidity, airflow and air conditions or their combinations, which are good for agriculture production. It is one of the most important natural resource prevailing on the Earth, including energy resources, energy resources and water resources. Guangxi is located at the tropical and subtropical monsoon climate zone, thus, the radiation flux energy is conducive to the use of climatic resources to develop agriculture in winter. To seek for the regional distribution and variation of climate resources, as well as the climatic potential productivity of winter crops over Guangxi, can be a great help to utilizing the agricultural climate resources in winter, providing the basis research and theoretical for agricultural development. In this study, the A2 scenario and B2 scenario structured in special report of emissions scenario (SRES)from IPCC can be chosen as the representative regional development climate changes in future. The A2 scenario described the rapid population growth and slow economic development; B2 scenario described the population and economic growth in the medium level, the ecological environment could be improved.The PRECIS (Providing Regional Climate for Impact Study) regional climate modeling system from Hadley Center/UK Met Office was used to generate the winter climate scenario dataset over Guangxi. The simulated temperature, precipitation and radiative flux, based on the year 1961 to 2010 as the basic standard period, can combine with using Miami Model and Thornthwait Montreal Model to estimate the temperature, moisture and climatic potential productivity in Guangxi. Finally, the special analysis of temporal and spatial distribution maps for the agriculture climate resources and climate productive potential in Guangxi province was done by GIS technology, to assess/project the future status of winter climatic resources and crop production potential in winter over Guangxi. The main results are as follows:(1) The result showed that the daytime temperature and the minimum temperature in winter in Guangxi was increased,A2 scenario was much more than B2 scenario. Winter precipitation in Guangxi was tended to decrease in winter with the B2 scenario trended to decrease much more. Winter average radiation intensity increases gradually to the interannual, the B2 scenario trended to increase higher. The increasing photoperiod and temperature was good for winter crop planting in Guangxi. With the less winter rainfall, soil moisture was much lower so that the water supply for crops will be inhibited.It was resulted that the agricultural production potential decreased with low level.(2) The winter average temperature decreases gradually from the south to the north in Guangxi, the most abundant heat area is Baise, Chongzuo, Fangcheng, Qinzhou, Beihai, and the low temperature area is in the region of Guilin, Liuzhou, Hechi. Under the B2/A2 scenario, the warm area in the South of Guangxi will further expand in the future, the 15 ℃ isotherm along the Tropic of cancer will be moved to the north of Liuzhou, Laibin and Hezhou, enhancing the winter heat condition in this area.(3) The winter precipitation showed a gradually decreasing from the east to the west in Guangxi, the most abundant precipitation area was in Guilin, Hezhou and Northern of Wuzhou, and water deficient area was in northern Baise, Hechi and Chongzuo. With the annual variability, winter precipitation will be estimated that it will become less in 2050s,and arid center gradually eastward to the Duan, Masan area. The western area rainfall may increase to alleviate the debt of moisture conditions in winter.(4) The average radiation intensity overall declined from the south of Guangxi to the north. Because of the altitude in northwest of Guangxi. the winter radiation intensity increased much rapidly more than other areas. The high strength winter radiation intensity was located not only the latitude area in Beihai, Yulin, but also the higher elevations of the western region in Baise. As the climate changes in the future, the average radiation intensity will further increase in Guangxi in 2050s.The high value area of the radiation intensity will further expand, and only a few area is lack of radiation above Northern of Guangxi.(5) Because of the effects of global warming, the temperature production potential is increasing and expanding. This will have a significant impact on the agricultural productivity to improve in winter.(6) The water potential productivity is affected by precipitation in winter decreasing, the lower value center is moving from the East to an area of Duan, Mashan, posing a threat to winter production in these areas.(7) The maximum evapotranspiration increased by the rising temperature, it will accelerate the further reduction of winter soil moisture. Due to affect by the interaction of the precipitation and maximum evapotranspiration in winter, winter climate production potential decline rapidly with the annual in Guangxi, which is consistent with the distribution of winter precipitation and water production potential.It proved that winter climate production potential of winter is mainly affected by the factor of water in Guangxi.