Abstract:

Based on the data of 10℃initial dates and upper air temperature of 39 stations in Cansu loess plateau from 1971 to 2004 the(limatic; feature and(irc;ulation background of 10℃initial dates were analyzed in the paper  meanwhile the(limatic; prediction method  WHS  eSCabhShed f01' the I'epl'eSentatlVe  SCatlOn Of  Xlfeng.  1}eSn1tS  S1lOW  that thel'e  al'e 3 earlier and 3 later areas where the dally mean tempel'atm'e  SCeadlly  OVPI'  10℃，which are located in Beidao} Lanzhou} Jingc;huan} and Huajialing}  Dongxiang} Minxian} respec;trvely; and the earliest 10℃initial date is April 14 in Beidao} the latest date is June 5 in Huajialing; and 10℃initial date ocurged later in Dingxi and Lingxia, earlier in Tianshui} Pingliang} Qingyang and Baiyin.  The、hanging trend of the day when the mean temperature steadily over 10℃in Cansu loess parts of the region in 1980s it is earlier in the north plateau has been earlier and earlier since 1990s} and it is part and later in the south part. 500 hPa } 700 hPa height later f;ellls in 1970s in
are(ontrolled by the ridge of high pressure from the north part of Qinghai一Xizang plateau to Xinjiang} and temperature fields、ontrolled by the broad
temperature ridge there and OLR flow fields(ontrolled by positive anomalies on 10℃initial date in earlier years;  on the(ontrary, 500 hPa} 700 hPa height fields a1.e influenced by the deep trough over Tarim Basin temperature 10T:initial fields affected by the broad temperatune trough over Xinjiang} and OLR flow fields influenced by negative anomalies on late in later years

Key words:  Gansu loess plateau, 10℃initial dates, distribution(harac, teristi<;Circ, ulation bac, k}round, forec, asting method

摘要：

用1971 - 2004年甘肃黄土高原39个站的气温10℃初日和高空资料，分析了其气候特征和环流背景，并建立了西峰代表站的气候预测方法。结果表明，甘肃黄土高原日平均气温稳定通过10℃的初日有3个偏早区，分别位于北道、兰州、泾川，有3个偏迟区，分别位于华家岭、东乡、岷县附
近;最旱的是北道为4月14日，最迟的是华家岭为6月5日。其空间分布特征是定西、临夏偏迟，天水、平凉、庆阳早，西北部的白银也较早。总的趋势是日平均气温稳定通过10℃的初日越来越早，特别是20世纪90年代以来，早的趋势更加明显;70年代大部分地方偏迟，80年代北部偏早，南部偏迟，90年代定西、临夏偏迟，其余偏早。初日早年，甘肃黄土高原500 hPa,700 hPa高度场受青藏高原北部到新疆宽广的高脊控制，温度场受青藏高原北部到新疆为宽广温度脊控制，OLR场受正距平控制;初日迟年，甘肃黄土高原500 hPa,700 hPa高度场受塔里木盆地深厚的低槽影响，温度场受新疆宽广的温度槽影响，OLR场受负距平影响。建立的西峰气温10℃初日模式的预测能力高。

关键词: 甘肃黄土高原, 10℃气温初日, 分布特征, 环流特征, 预测方法