基于SPEI的近百年天津地区气象干旱时空演变特征

王敏, 尹义星, 陈晓旸, 郭阳, 徐梅, 罗传军

Changing characteristics of meteorological drought in Tianjin for almost one century based on standardized precipitation evapotranspiration index

WANG Min, YIN Yixing, CHEN Xiaoyang, GUO Yang, XU Mei, LUO Chuanjun

图4 1921—2016年不同时期天津四季极旱(a)、重旱(b)、中旱(c)、轻旱(d)和所有等级干旱(e)的平均频率(1~6分别代表6个时期;7代表全时期)

Fig.4 The average frequency of extreme drought (a), severe drought (b), moderate drought (c), mild drought (d) and drought with all levels (e) in four seasons of different periods during 1921-2016 in Tianjin (Numbers 1 to 6 represent six periods, respectively; number 7 represent whole period)