Land surface albedo (LSA) is an important parameter in surface-energy budget studies and process-based models. Availability of LSA on a continental scale from the geostationary platform can be very useful in various applications and modelling activities. A study has been carried out to develop a narrow to broadband albedo conversion algorithm for estimating broadband LSA over India and surrounding from INSAT-3D (I3D) Imager observations. An atmospheric radiative transfer model was used to simulate the at-sensor reflectivity corresponding to two spectral bands of I3D Imager located in visible (0.55–0.75 μm) as well as shortwave infrared (1.55–1.70 μm) regions and a shortwave broadband spectral region (0.40–2.5 μm) for diverse land-atmospheric characteristics by assuming the surfaces as Lambertian targets. Then a mathematical relationship between reflectivity of two Imager bands and a shortwave broadband was developed based upon radiative transfer model simulation results, which yielded narrow-to-broadband conversion coefficients. A separate set of narrow to broadband conversion coefficients for major land covers were generated for I3D Imager sensor. Using the proposed method and coefficients, broadband LSA maps were generated over India and surrounding regions. Daily and 15-Day composite LSA products have also been successfully generated on continental scale. The broadband LSA derived from I3D captured the albedo range successfully for various land covers, including water (0.03–0.07), desert (0.30–0.55), crop (0.12–0.18), forest (0.11–0.17), soil (0.09–0.26) and snow (0.41–0.65). Comparison of I3D-derived LSA by the proposed algorithm with the Moderate Resolution Imaging Spectroradiometer (MODIS) albedo product showed a very good match (R²=0.88 and root mean square error, RMSE=0.046). The proposed algorithm is being successfully used for operational retrieval of Daily and 15-Day composite LSA on Indian Space Research Organisation’s MOSDAC (Meteorological and Oceanographic Data Archival Centre) and India Meteorology Department’s IMDPS (IMD Processing System) sites.

地表反照率 (LSA) 是地表能量收支研究和基于过程的模型中的一个重要参数。来自地球静止平台的 LSA 在大陆范围内的可用性在各种应用和建模活动中非常有用。已经开展了一项研究，以开发一种窄到宽带反照率转换算法，用于通过 INSAT-3D (I3D) 成像仪观测估计印度和周边地区的宽带 LSA。大气辐射传输模型用于模拟对应于位于可见光 (0.55-0.75 μm) 以及短波红外 (1.55-1.70 μm) 区域和短波宽带光谱区域 ( 0.40–2.5 μm）通过假设表面为朗伯目标来获得不同的陆地-大气特征。然后，基于辐射传输模型仿真结果，建立了两个成像仪波段反射率与短波宽带之间的数学关系，得出窄带到宽带的转换系数。为 I3D Imager 传感器生成了一组单独的主要土地覆盖的窄到宽带转换系数。使用所提出的方法和系数，在印度和周边地区生成了宽带 LSA 地图。每日和 15 天复合 LSA 产品也已在大陆范围内成功生成。来自 I3D 的宽带 LSA 成功捕获了各种土地覆盖的反照率范围，包括水 (0.03–0.07)、沙漠 (0.30–0.55)、作物 (0.12–0.18)、森林 (0.11–0.17)、土壤 (0.09–0.26) ) 和雪 (0.41–0.65)。² =0.88 和均方根误差，RMSE=0.046）。所提出的算法已成功用于印度空间研究组织的 MOSDAC（气象和海洋数据档案中心）和印度气象部门的 IMDPS（IMD 处理系统）站点上的每日和 15 天复合 LSA 的操作检索。