中文摘要：

利用2003年至2005年秋季在南海多个航次的现场观测数据，研究了南海北部海区遥感反射率的变化，并分析了用于全球海洋叶绿素a浓度反演的OC2和OC4模型在本海区的适用性。结果表明，在南海北部海域，OC2和OC4模型高估了叶绿素a浓度，高估范围一般约在80％-200％之间，其中最高可达640％，即OC2和OC4模型并不适用于南海海域。在此基础上，根据现场实测的表观光学数据，利用遥感反射率比值（Rrs（433）／Rrs（555））与叶绿素a浓度的关系建立了两套能够精确反演南海北部海域叶绿素a浓度的本地化经验算法——算法1和算法2，并利用其对南海北部海域的叶绿素a浓度进行反演。结果表明，由本地化模型反演得到的叶绿素a浓度与实测的叶绿素a浓度具有较好的相关关系，其平均相对偏差分别为51％和53％，相关系数为0．75。

英文摘要：

Bio-optical data and chlorophyll-a concentration obtained in the autumn of 2003 and 2005 during the cruises in the northern South China Sea （NSCS） are analyzed. The results show that the current NASA global algorithms, namely OC2 and OC4, generally overestimate chlorophyll-a concentration by 80% to 200%, and even up to 640%, indicating that OC2 and OC4 algorithms are unsuitable for NSCS. Based on in-situ apparent optical data, we establish two local algorithms of OC2 and OC4 by using the relationship between Rrs（443）/Rrs（555） and chlorophyll-a concentration. It is found that the results retrieved by using the local algorithms are better than those by NASA algorithms. The average relative biases of the local algorithms 1 and 2 are 51% and 53 %, respectively. The correlation coefficients are 0.75, showing a relatively high correlation between the retrieved chlorophyll-a concentration and the in-situ one in the NSCS.