不同冬小麦品种产量和节水性状差异及对供水的反应

以24个冬小麦品种(系)为材料,在不同的灌水处理下,研究了产量、产量构成因素和抗旱指数的品种差异。结果表明,灌水处理间与品种间产量差异均极显著,灌水与品种互作差异显著。2水处理产量高于4水。石4185,冀 5579,石麦12等19个品种2水处理产量高于4水,多丰2000,师栾02-1,良星99等5个品种4水产量高于2水。分别以2水处理和4水处理下的产量作为水地产量计算抗旱指数,得出抗旱型,不抗旱型和中间型比例分别为4．2％, 29．2％,66．6％和20．8％,20．8％,58．4％。综合分析认为石麦12,冀5579和石新618等产量和节水综合性状较好的品种更适于节水栽培。

Seasonal variability in tropical and subtropical convective and stratiform precipitation of the East Asian monsoon

Seasonal variations in tropical and subtropical convective and stratiform precipitation of the East Asian monsoon are analyzed using 10-year (1998-2007) Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) rain products (2A25). Datasets from the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) 24 general circulation models (GCMs) are evaluated using TRMM PR rain products in terms of their ability to simulate convective and stratiform precipitation and their deficiencies. The results show that Asian monsoon convective and stratiform precipitation increases significantly after onset of the summer monsoon, but the percentage of convective precipitation clearly decreases over tropical areas while it increases in subtropical regions. The GCMs simulate well the seasonal variation in the contribution of Asian monsoon subtropical convective precipitation to the total rainfall; however, the simulated convective precipitation amount is high while the simulated stratiform precipitation amount is low relative to TRMM measurements, especially over the Asian monsoon tropical region. There is simultaneous TRMM-observed convective and stratiform precipitation in space and time, but GCMs cannot simulate this relationship between convective and stratiform precipitation, resulting in the deficiency of stratiform precipitation simulations.