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w słowach kluczowych: użytkowanie i pokrycie terenu

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Thermal stress and urban heat island effect in Jorhat urban environment as a result of changing land use and land cover

Neog Rituraj, Hazarika Jiten

Acta Geophysica

2022

Vol. 70, no 6

2771--2783

The objective of the study is to determine the impact of land use and land cover (LULC) change on land surface temperature (LST) and thermal stress at Jorhat from 2009 to 2021. The experiment used Landsat TM (Thematic Mapper) for 2009 and OLI (Operational Land Imager)/TIRS (Thermal Infrared Sensor) for 2021 from earth.explorer.usgs.gov. Landsat data were employed to calculate the LST and LULC changes. Utilizing UTFVI (urban thermal field variance index), thermal stress over the ground surface has been computed. Thermal discomfort is computed simultaneously using the relative strain index (RSI) and net effective temperature (NET) index. Jorhat evidenced significant rise in built-up land to 281.25 hectares with reduced vegetation cover of 480.96 hectares from 2009 to 2021. These modifications caused significant rises in LST of 4.28 °C, 2.33 °C and 3.01 °C in September, October and December from 2009 to 2021. According to UTFVI from 2009 to 2021, Jorhat experienced declining ecologically excellent area with a rising proportion of ecologically worse land. In September and October 2009, the Jorhat city had just 10 days of bioclimatic discomfort and 19 days of bioclimatic comfort, as opposed to 24 and 10 days in 2021, respectively. Similarly, NET estimated 21 very hot days in October 2021, as opposed to just 9 days in 2009. Compared to 2009, there are now 6 and 4 days in December 2021 that are classified as warm or slightly hot, respectively. This leads to the conclusion that Jorhat's thermal condition is significantly impacted by changes in land use and land cover.

Analysis of land use/land cover change in Adei watershed, Central Highlands of Ethiopia

Dinka Megersa Olumana, Chaka Degefa Dhuga

Journal of Water and Land Development

2019

no. 41

146--153

Land use/land cover changes (LULCC) at Adei watershed (Ethiopia) over a period of 23 years (1986–2009) has been analysed from LANDSAT imagery and ancillary data. The patterns (magnitude and direction) of LULCC were quantified and the final land use/land cover maps were produced after a supervised classification with appropriate post-processing. Image analysis results revealed that the study area has undergone substantial LULCC, primarily a shift from natural cover into managed agro-systems, which is apparently attributed to the increasing both human and livestock pressure. Over the 23 years, the aerial coverage of forest and grass lands declined by 8.5% and 4.3%, respectively. On the other hand, agricultural and shrub lands expanded by 9.1% and 3.7%, respectively. This shows that most of the previously covered by forest and grass lands are mostly shifted to the rapidly expanding farm land use classes. The findings of this study suggested that the rate of LULCC over the study period, particularly deforestation due to the expansion of farmland need to be given due attention to maintain the stability and sustainability of the ecosystem.

Zmiany użytkowania i sposobu pokrycia terenu w zlewni Adei (Etiopia) analizowano w ciągu 23 lat (1986–2009) z użyciem obrazów LANDSAT i dodatkowych danych. Oceniono ilościowo schemat zmian (wielkość i kierunek) oraz wykonano mapy użytkowania i pokrycia terenu po odpowiednim przetworzeniu danych. Analiza obrazów ujawniła, że badany obszar podlegał znaczącym zmianom – głównie od naturalnego pokrycia do gospodarczych agrosystemów, co wynikało z rosnącej presji ze strony człowieka i zwierząt gospodarskich. W ciągu 23 lat powierzchnie leśne i trawiaste zmalały odpowiednio o 8,5 i 4,3%, a powierzchnie użytkowane rolniczo i tereny zakrzaczone powiększyły się odpowiednio o 9,1 i 3,7%. Oznacza to, że tereny uprzednio zajmowane przez lasy i systemy trawiaste zostały zajęte przez tereny rolnicze. Przeprowadzone badania sugerują, że należy zwrócić szczególną uwagę na szybkie zmiany pokrycia powierzchni terenu, aby utrzymać stabilność i trwałość ekosystemu.