知识与财富的链接
在非线性误差增长理论的基础上,研究了位势高度场与温度场月和季节时间尺度可预报期限的时空分布特征,结果表明:(1)在500 hPa位势高度场上,年平均月和季节尺度可预报期限的空间分布都存在明显的南北经向性差异,其中在热带地区月和季节尺度可预报期限都为最大,月尺度可预报期限都在6个月以上, 其中最高值超过了9个月,而季节尺度可预报期限基本上都在8个月以上,其中最高值超过了11个月;从热带地区到南北半球中纬度地区,随着纬度的升高,月和季节尺度可预报期限也迅速减少。(2)在500 hPa位势高度场上,月和季节尺度可预报期限的空间分布都有明显的季节变化。冬季月和季节尺度可预报期限除了在热带地区较大外,在北太平洋和邻近的北美西北部地区、北大西洋地区以及南极地区,冬季月和季节尺度可预报期限也相对周围地区较高。夏季除了北非和西亚地区月和季节尺度可预报期明显大于冬季以外,大部分地区月和季节尺度可预报期限比冬季明显减少。(3)500 hPa温度场月和季节尺度可预报期限的空间分布以及随季节的变化特征基本上与高度场相同,只是在热带大部分地区,高度场相对温度场来说月和季节尺度可预报性更高,更适合用来作长期预报。
Based on the nonlinear error growth dynamics introduced by the authors recently,the temporal-spatial distributions of predictability limit of monthly and seasonal mean geopotential height and temperature fields are investigated.The results are summarized as follows:(i) For the 500-hPa height field,the predictability limit of monthly and seasonal means shows obvious differences between the tropics and middle-high latitudes.The predictability limit of monthly and seasonal means is largest in the tropics,and decreases quickly from the tropics to middle-high latitudes of southern and northern hemispheres.In the tropics,the predictability limit of monthly means is beyond 6 months with the maximum value exceeding 9 months,and the predictability limit of seasonal means is beyond 8 months with the maximum value exceeding 11 months.However,in mid-high latitudes,the predictability limit of monthly means is only 2-3 months,and the predictability limit of seasonal means is only 4-5 months.(ii) The spatial distributions of predictability limit of monthly and seasonal means vary obviously with season.In winter,the predictability limit of monthly and seasonal means is large in the other regions besides the tropics,including the North Pacific,the North Atlantic,and Antarctic,where the predictability limit is much higher than that in summer.In summer,the predictability limit of monthly and seasonal means decreases in the most regions except North Africa and West Asia.(iii) Temporal-spatial distributions of predictability limit of monthly and seasonal mean 500-hPa temperature fields are similar to those of 500-hPa geopotential height field.In the most tropical regions,however,the predictability limit of 500-hPa geopotential height field is higher than that of 500-hPa temperature field,thus the former is more applicable as the long-term predictand than the latter.
