*Article* **Combining MODIS and National Land Resource Products to Model Land Cover-Dependent Surface Albedo for Norway**

#### **Ryan M. Bright \* and Rasmus Astrup**

Norwegian Institute of Bioeconomy Research, P.O. Box 115, 1431 Ås, Norway; rasmus.astrup@nibio.no **\*** Correspondence: ryan.bright@nibio.no; Tel.: +47-9747-7997

Received: 25 January 2019; Accepted: 28 March 2019; Published: 10 April 2019

**Abstract:** Surface albedo is an important physical attribute of the climate system and satellite retrievals are useful for understanding how it varies in time and space. Surface albedo is sensitive to land cover and structure, which can vary considerably within the area comprising the effective spatial resolution of the satellite-based retrieval. This is particularly true for MODIS products and for topographically complex regions, such as Norway, which makes it difficult to separate the environmental drivers (e.g., temperature and snow) from those related to land cover and vegetation structure. In the present study, we employ high resolution datasets of Norwegian land cover and structure to spectrally unmix MODIS surface albedo retrievals (MCD43A3 v6) to study how surface albedo varies with land cover and structure. Such insights are useful for constraining land cover-dependent albedo parameterizations in models employed for regional climate or hydrological research and for developing new empirical models. At the scale of individual land cover types, we found that the monthly surface albedo can be predicted at a high accuracy when given additional information about forest structure, snow cover, and near surface air temperature. Such predictions can provide useful empirical benchmarks for climate model predictions made at the land cover level, which is critical for instilling greater confidence in the albedo-related climate impacts of anthropogenic land use/land cover change (LULCC).

**Keywords:** spectral unmixing; empirical modeling; linear endmember; forest cover; forest management; forest structure; BRDF/Albedo; NDSI Snow Cover
