Land use alternatives are sought to boost agricultural income and productivity in Hainan Island, China.Regional differences exist in crop limitations, such as typhoon risk, low temperatures, poor soil fertility, and d...Land use alternatives are sought to boost agricultural income and productivity in Hainan Island, China.Regional differences exist in crop limitations, such as typhoon risk, low temperatures, poor soil fertility, and drought. In this study a crop zonation was made for a range of crops, among which is banana, as a way to: 1)establish areas for potential expansion for banana, and 2) identify limitations and options for crop and land management. A spatial soil and terrain database of Hainan Island (1:250 000) was linked to the automated land evaluation system (ALES). The qualitative models were verified by comparing suitability maps with actual land use. The results may support policy formulation on issues such as alternatives to current land use, assessment of best management practices, and the need for fertilizer programmes.展开更多
The next-generation weather radar(NEXRAD) can generally capture the spatial variability of rainfall fields,but fails to provide accurate depth measurements.A systematic strategy to evaluate the accuracy of radar data ...The next-generation weather radar(NEXRAD) can generally capture the spatial variability of rainfall fields,but fails to provide accurate depth measurements.A systematic strategy to evaluate the accuracy of radar data in depth measurement and its performance in hydrologic model is outlined.Statistical evaluation coefficients are calculated by comparing NEXRAD data with individual raingauges as well as subbasin-averaged interpolations,and point-and surface-average factors are introduced to revise radar data successively.Hydrologic simulations are then performed with a distributed hydrologic model,called basin pollution calculation center(BPCC) with both raingauge observations and revised NEXRAD estimates inputs.The BPCC model is applied to Clear Creek Watershed,IA,USA,on an hourly scale,and the calibration and validation parameters are semi-automatically optimized to improve manual calibration shortcomings.Results show that hydrographs generated from both gauge and NEXRAD are in good agreement with observed flow hydrographs.Coefficient statistics reveal that NEXRAD contributes to model performance,indicating that NEXRAD data has the potential to be used as an alternative source of precipitation data and improve the accuracy of hydrologic simulations.展开更多
基金Project supported by United Nation Development Programme (UNDP, No. CPR/96/105/A99).
文摘Land use alternatives are sought to boost agricultural income and productivity in Hainan Island, China.Regional differences exist in crop limitations, such as typhoon risk, low temperatures, poor soil fertility, and drought. In this study a crop zonation was made for a range of crops, among which is banana, as a way to: 1)establish areas for potential expansion for banana, and 2) identify limitations and options for crop and land management. A spatial soil and terrain database of Hainan Island (1:250 000) was linked to the automated land evaluation system (ALES). The qualitative models were verified by comparing suitability maps with actual land use. The results may support policy formulation on issues such as alternatives to current land use, assessment of best management practices, and the need for fertilizer programmes.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2007CB407202)
文摘The next-generation weather radar(NEXRAD) can generally capture the spatial variability of rainfall fields,but fails to provide accurate depth measurements.A systematic strategy to evaluate the accuracy of radar data in depth measurement and its performance in hydrologic model is outlined.Statistical evaluation coefficients are calculated by comparing NEXRAD data with individual raingauges as well as subbasin-averaged interpolations,and point-and surface-average factors are introduced to revise radar data successively.Hydrologic simulations are then performed with a distributed hydrologic model,called basin pollution calculation center(BPCC) with both raingauge observations and revised NEXRAD estimates inputs.The BPCC model is applied to Clear Creek Watershed,IA,USA,on an hourly scale,and the calibration and validation parameters are semi-automatically optimized to improve manual calibration shortcomings.Results show that hydrographs generated from both gauge and NEXRAD are in good agreement with observed flow hydrographs.Coefficient statistics reveal that NEXRAD contributes to model performance,indicating that NEXRAD data has the potential to be used as an alternative source of precipitation data and improve the accuracy of hydrologic simulations.
