Frequency of Fires in the Miombo Woodland of the Gilé National Park. Province of Zambezia

Fires occur in a widespread manner in various types of vegetation cover at national level, and are often associated with human hunting, grazing and above all the practice of itinerant agriculture. With the purpose to propose the map of frequency of fire, remote sensing data was collected from 2014 to 2018, using the Moderate Resolution Image Spectroradiometer (MODIS) of the burned area (MCD64A1), which allowed the construction of the map of frequency and intensity of fires, associated with data collected in 59 plots on field. It was observed that the Gilé National Park (PNAG) records an average fire frequency of 0.38 times/year and the return interval of 5.38 years, and an average fire return interval of 2.62 years. During the study period, the PNAG burned 92.8% of the area, which means that on average for each year it burned about 18.56% of its area, there are no significant differences in relation to the area burned per year (p> 0.942037) but there are significant differences in relation to the area burned per month (p <1.24e-07).

Evaluating the Spatial Representativeness of the MODerate Resolution Image Spectroradiometer Albedo Product (MCD43) at AmeriFlux Sites

Land surface albedo is a key parameter in regulating surface radiation budgets. The gridded remote sensing albedo product often represents information concerning an area larger than the nominal spatial resolution because of the large viewing angles of the observations. It is essential to quantify the spatial representativeness of remote sensing products to better guide the sampling strategy in field experiments and match products from different sources. This study quantifies the spatial representativeness of the MODerate Resolution Image Spectroradiometer (MODIS) (collection V006) 500 m daily albedo product (MCD43A3) using the high-resolution product as intermediate data for different land cover types. A total of 1820 paired high-resolution Landsat Thematic Mapper (TM) and coarse-resolution (MODIS) albedo data from five land cover types were used. The TM albedo data was used as the spatial-complete high resolution data to evaluate the spatial representativeness of the MODIS albedo product. Semivarioagrams were estimated from 30 m Landsat data at different spatial scales. Surface heterogeneity was evaluated with sill value and relative coefficient of variation. The 30 m Landsat albedo data was aggregated to 450 m–1800 m using two different methods and compared with MODIS albedo product. The spatial representativeness of MODIS albedo product was determined according to the surface heterogeneity and the consistency of MODIS data and the aggregated TM value. Results indicated that for evergreen broadleaf forests, deciduous broadleaf forests, open shrub lands, woody savannas and grasslands, the MODIS 500 m daily albedo product represents a spatial scale of approximately 630 m. For mixed forests and croplands, the representative spatial scale was approximately 690 m. The difference obtained was primarily because of the complexity of the landscape structure. For mixed forests and croplands, the structure of the landscape was relatively complex due to the presence of different forest and plant types in the pixel area, whereas the other landscape structures were considerably simpler.