ASAS = NASA's Advanced Solid-state Array Spectroradiometer: 1988 -2000

The Advanced Solid-State Array Spectroradiometer (ASAS) data collection contains data collected by the ASAS sensor flown aboard NASA aircraft. A fundamental use of ASAS data is to characterize and understand the directional variability in solar energy scattered by various land surface cover types (e.g., crops, forests, prairie grass, snow, or bare soil). The sensor's Bidirectional Reflectance Distribution Function determines the variation in the reflectance of a surface as a function of both the view zenith angle and solar illumination angle.

The ASAS sensor is a hyperspectral, multiangle, airborne remote sensing instrument maintained and operated by the Laboratory for Terrestrial Physics at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The ASAS instrument is mounted on the underside of either NASA C-130 or NASA P-3 aircraft and is capable of off-nadir pointing from approximately 70 degrees forward to 55 degrees aft along the direction of flight. The aircraft is flown at an altitude of 5000 - 6000 meters (approximately 16,000 - 20,000 ft.).

Data in the ASAS collection primarily cover areas over the continental United States, but some ASAS data are also available over areas in Canada and western Africa. The ASAS data were collected between 1988 and 1994.

先进固态阵列光谱辐射计（Advanced Solid-State Array Spectroradiometer，以下简称ASAS）数据集收录了搭载于美国国家航空航天局（National Aeronautics and Space Administration，以下简称NASA）航空器的ASAS传感器所获取的观测数据。ASAS数据的核心应用之一是表征并解析各类陆地地表覆盖类型（如农作物、森林、草原草本植被、积雪或裸土）所散射的太阳能的方向变异性。该传感器的双向反射分布函数（Bidirectional Reflectance Distribution Function，以下简称BRDF）可用于确定地表反射率随观测天顶角与太阳光照角度变化的规律。
ASAS传感器是一款高光谱、多角度机载遥感仪器，由位于马里兰州格林贝尔特的NASA戈达德太空飞行中心（Goddard Space Flight Center）陆地物理实验室（Laboratory for Terrestrial Physics）负责运维与操作。该仪器搭载于NASA C-130或NASA P-3航空器的机身下方，可沿飞行方向实现约70°前视至55°后视的离天底指向。作业飞行高度介于5000至6000米（约16000至20000英尺）之间。
ASAS数据集的覆盖范围以美国本土为主，同时也包含部分加拿大与西非地区的观测数据。该数据集的观测时段为1988年至1994年。