Recent changes in the level of Lake Naivasha, Kenya, as an indicator of equatorial westerlies over East Africa
Recent changes in the level of Lake Naivasha, Kenya, as an indicator of equatorial westerlies over East Africa
复制标题
肯尼亚奈瓦沙湖水位的近期变化，作为东非赤道西风的指标
DOI：
10.1007/bf00133223
复制
发表时间：
1979
期刊：
影响因子：
4.8
通讯作者：
A. Beresford
中科院分区：
文献类型：
--
作者：
C. E. Vincent;T. Davies;A. Beresford
此前未发表的肯尼亚奈瓦沙湖1880年至1976年水位记录已被分析，与附近维多利亚湖的水位记录几乎没有相似之处。两湖水位的年际变化没有明显的相关性(在5%)，两个记录的光谱分析也没有共同的显著峰值。这两个湖泊的水位变化与北大西洋冬季环流强度之间存在显著的相关性，相反方向的相关系数表明了重要但不同的大范围气候联系。奈瓦沙湖水位的主要上升发生在5月和9月。维多利亚湖的水位主要在5月份上升，12月份略有上升。东非降雨量一般在4月和11月，与维多利亚湖的变化相对应。然而，肯尼亚高原地区的降雨记录显示，8月的降雨量达到峰值，11月的降雨量很少。高原气象站赤道站7、8、9月的降雨量与9月奈瓦沙的水平变化高度相关(达1%显著水平)。8月份，高原站的风是西风，而较低层的站经历了更干燥的S.E.交易。奈瓦沙湖的水位变化表明，来自西非的湿空气在信风和200毫巴的东风急流之间穿透的程度发生了变化。
A previously unpublished record of lake levels from Lake Naivasha, Kenya from 1880 to 1976 has been analysed and shows little similarity to the level record from nearby Lake Victoria. Level changes from year to year of the two lakes show no significant correlation (at 5%) and spectral analysis of the two records shows no common significant peaks. Both lakes show significant correlations between their level changes and the strength of the North Atlantic winter circulation, with the correlation coefficients in opposing directions indicating important, but different, large scale climatic links.Lake Naivasha's major level increases occur during May and September. Lake Victoria's level increases mainly in May with a small December increase. East African rainfall is generally during April and November, corresponding with Lake Victoria's changes. Rainfall records from Kenyan highland areas, however, show an August rainfall peak and little rainfall in November. Rainfall amounts from Equator, a highland meteorological station, for July, August and September are highly correlated (at 1% significance level) with the change in Naivasha's level during September. Winds at the highland stations are westerly during August while the lower level stations experience the drier S.E. Trades. The level changes of Lake Naivasha indicate changes in the extent of the penetration of moist air from West Africa between the Trade winds and the 200 mb easterly jet.