Revealing changes in the boundary layer height in different land use classes the Case study of Lorestan province

The height of the boundary layer is one of the most important determining factors, the extent of mixing of pollutants and suspended particles and the quality of air near the surface of the earth. The main goal of this research is to reveal the relationship between land cover changes and boundary layer height changes during the last 3 decades in Lorestan province. In this regard, two sets of data were used, which include the land cover classes of the MODIS sensor and the height of the boundary layer of the ECMWF climate database version ERA5. These data were selected on a monthly scale (January) to check the cold period and (July) to check the warm period and were checked in 7 time periods with 5-year steps during the statistical period of 1990-2020. In this research, the cross-matrix analysis technique was used in the ARC-GIS environment and the average height of the boundary layer on each land use was extracted and compared in 7 time steps of 5 years, separately from the cold and warm periods of the year. The results showed that firstly, the height of the boundary layer during the warm period is significantly higher than the cold period of the year, and secondly, the minimum and maximum spatial pattern of the boundary layer height in the cold and warm periods of the year is different in the province. In the cold period, the maximum height of the boundary layer is in the western parts. and southwest (low-altitude lands with forest cover), while in the warm period of the year, the maximum boundary layer is concentrated in the barren and mountainous lands of the east of the province. In addition, it was observed that in the hot period of the year, agricultural lands with a boundary layer height of 1263 and pasture lands with a boundary layer height of 1243 have the highest boundary layer height among the investigated use classes, while in the cold period of the year, urban and residential lands with a height of 192 meters, It has the highest boundary layer height and the spatial average of the boundary layer height of the province has had an increasing trend