中国东部海域叶绿素时空变化经验正交分析及探讨  

EOF analysis of SeaWiFS Chlorophyll a concentration in the East China Sea waters

作　　者：胡松[1] 吴奇峰[1] 

机构地区：[1]上海海洋大学海洋科学学院,海洋生态系统与环境实验室,上海201306

出　　处：《水产学报》2011年第6期890-896,共7页Journal of Fisheries of China

基　　金：上海市科委重点项目(09320503700);上海市教委优秀青年基金(B-8101-09-0237);上海市教委高校第5期海洋环境工程重点学科建设项目(J50702)

摘　　要：利用经验正交函数(EOF)分析了中国东部海域SeaWiFS叶绿素a(1998—2007年)时空变化主要模态,对前3个模态进行了功率谱分析。气候平均结果表明,叶绿素a空间总体分布特征为近海高、外海低,季节变化为春季3—4月最高,夏季6—7月最低。EOF前3个模态所占的贡献率分别为84.89%,3.38%,1.06%。第一模态权重占绝对优势,空间分布与气候平均场基本一致,时间序列表明1998年和2000年为叶绿素a浓度典型低值年,2007年为叶绿素a浓度典型高值年,线性拟合表明总体叶绿素a浓度呈缓慢增加趋势。第二模态主要体现为季节变化,功率谱显著周期为12个月,空间上呈长江口、杭州湾及浙江沿岸海域为正,离岸海域为负的反位相分布特征。第三模态功率谱显著周期为12个月和6个月,以122.9°E,32.2°N为中心的区域呈负相位,黄海和浙江外海区域呈正相位分布,这可能受沿岸流、长江径流转向路径和台湾暖流变化所影响。The temporal-spatial distributions of SeaWiFS Chlorophyll a concentration（1998—2007）in the East China Sea waters（116°-135°E,21°-42°N）were analyzed by using Empirical Orthogonal Function（EOF）method.The first three dominant EOF modes were analyzed using power spectrum.For spatial variability,the climatological SeaWiFS Chlorophyll a shows that the concentrations of Chlorophyll a are high near coast and low offshore;for seasonal variability,the monthly climatological SeaWiFS Chlorophyll a is highest in spring（March-April）and lowest in summer（June-July）.The first three modes of EOF contribute 84.89%,3.38%,and 1.06% of variation,respectively.The first mode accounts for most of the variability;the spatial distribution is consistent with the climatology mean;the time coefficients indicate that years 1998 and 2000 have lower Chlorophyll a than normal years,while year 2007 has higher Chlorophyll a than normal years;the linear fitting of Chlorophyll a concentrations shows a weakly positive trend.The second mode displays the seasonal variability with a significant period of 12 months using discrete power spectral analysis;the area near the Yangtse River Estuary,the Hangzhou Bay and along Zhejiang Province coast is positive and the other areas are negative.The time coefficients of the third mode show two significant periods of 12 months and 6 months;an area centered at 122.95°E,32.24°N are negative while the Yellow Sea and the area offshore Zhejiang Province are positive,which is probably related with the variability of along-shore currents,expansion of the Changjiang River diluted water and Taiwan Warm Current.

关 键 词：叶绿素A EOF分析 时空分布 中国东部海域 

分 类 号：P735[天文地球—海洋生物学]