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Investigating the Influence of Urban River Valleys on Meteorological Parameters at the Local Scale as a Factor for urban sustainability - Case study: Farahzad River Valley Full text
2023
Allahyari, Hadis | Salehi, Esmael | Zebardast, Lobat | Jafari, Hamidreza
Four regions of the Farahzad River Valley with different topography were selected to fully survey it and study the effects of morphology on local climate. then one of the hot days of the month of June 2021 (June 6th) was selected because the wind speeds increase in spring. According to the comparison of the simulation results with the existing site plans, the temperature in area 3 was the highest, 39.60 degrees, and the wind speed was 3.57 m/s. On the other hand, the study and analysis of the maps showed that the temperature of the roads in regions 3 and 4 were higher than the other two regions with a temperature range of 37.69-38.40, so the presence of impervious asphalt surfaces on the roads is very effective in increasing the air temperature in these areas. Comparisons also showed that tall buildings and vegetation create shaded areas and increase wind speed. Based on this, two scenarios were designed. In the first scenario, doubling the height of buildings increased wind speed in Region 3 by 3.42 m/s and decreased temperatures by 1.59 degrees. In the second scenario, when tall trees were planted at certain distances around the streets, the temperature in Region 3 decreased by 1.68 degrees and the wind speed increased by 1.68 m/s. The results show that the differences in the topography of urban valleys cause ventilation of the environment and that the effect of this feature in other environments is more effective through planting than through buildings.
Show more [+] Less [-]Economic Impact of Climate Change on Agriculture: A Study of India and its Neighbouring Countries Using ARDL Approach Full text
2023
Mashud Ahmed and Paramita Saha
This study aims to analyze the association between the share of agriculture in GDP and changes in climatic variables, notably per capita CO2 emissions and temperature change, using time series data of India, Bangladesh, and Nepal for the period 1961-2018. The ARDL bounds testing method was applied to analyze the relationships among the research variables for both short-term and long-term. The results revealed that in the long run, per capita CO2 emissions and temperature change have no statistically significant relationship with India and Nepal’s share of agriculture in GDP. However, temperature change has demonstrated a positive and statistically significant relationship with the share of agriculture in Bangladesh’s GDP. Temperature change has a significant and adverse impact on the share of agriculture in India’s GDP in the short run, whereas CO2 has no significant effect. In the short run, CO2 shows a positive and significant connection with the share of agriculture in Bangladesh’s GDP. Still, temperature change is negatively and significantly associated with the proportion of agriculture in the nation’s GDP. Different lag values of both CO2 and temperature change have significant relationships with the share of GDP in agriculture in the short run in Nepal. As agriculture is a key source of GDP for all three countries, it is vital to implement suitable policies and make plans and strategies to mitigate climate change’s harmful consequences in agriculture.
Show more [+] Less [-]Evapotranspiration Over the Indian Region: Implications of Climate Change and Land Use/Land Cover Change Full text
2023
Garima Singh and Sudhir Kumar Singh
Evapotranspiration (ET) plays a significant role in climatic studies, directly influencing the hydrological cycle, energy balance equation, and surface vegetation. ET comprises three components: bare soil or ground evaporation, evaporation, and transpiration, in which vegetation removes water influenced by food grain production. In turn, soil moisture availability depends on precipitation characteristics over land, surface net radiation, and wind speed are the major climatic factors that together determine the magnitude of ET. This controls moisture availability in the lower troposphere, hence atmospheric stability, chances of cloud formation, and precipitation. Though the study of evapotranspiration is important for determining agricultural water consumption and analyzing drought situations, there is a lot of uncertainty in its accurate estimation. Land use/Land cover changes (LULCC) occurring throughout the Indian subcontinent have been found to affect the characteristics of low to moderate rainfall events and surface temperature extremes (Halder et al. 2016). A global warming scenario will change the hydrological cycle, and the impact of anthropogenic factors has also necessitated the need to understand the mechanisms that control changes in ET over India. In this study, we want to analyze the relationship between transpiration and the Normalized Difference Vegetation Index (NDVI) and investigate the relationship between canopy interception with respect to NDVI all over the Indian region. Attempts have been made to assess the impact of changes in climate and LULC on ET and its three components over the Indian region from 1981 till the present time. The monsoon season increases precipitation, and soil evaporation is found to increase at first, along with an increase in NDVI followed by canopy evaporation and transpiration. It is noted that changes in precipitation and LULCC across the Indian subcontinent have contributed significantly to changes in ET in different seasons. As variability in surface net radiation also plays an important role in controlling changes in total ET, it is being investigated.
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