Seminar Title:
Analyzing and Forecasting Urban Growth over Coastal Indian Cities and their association with Rainfall and Temperature
Seminar Type:
Departmental Seminar
Department:
Earth and Atmospheric Sciences
Speaker Name:
Asmita Mukherjee
Speaker Type:
Student
Venue:
ER 303 Class Room
Date and Time:
27 Dec 2024 4:45 PM
Contact:
89815 16022
Abstract:
Urbanization in Indian megacities is pacing at an unparalleled and irreversible rate. This
phenomenon is mostly driven by population migration and thereby exerts tremendous pressure
on the local environment. The current study analyzes the growth dynamics, forecasts future
urban growth of four major coastal Indian cities (viz., Mumbai, Chennai, Kochi, and
Vishakhapatnam) and highlights their association with rainfall and temperature. Land Use Land
Cover (LULC) thematic datasets are classified using Landsat imageries using Random Forest
algorithm for the years 1990 to 2023. These datasets are used to explore the capabilities of deep
learning (DL) models like CNN and ConvLSTM for accurately projecting the future urban
growth in the considered cities. The variability of the four LULC classes, viz., (i) urban built-up,
(ii) vegetation, (iii) water body, (iv) agriculture and barren land, indicated that urban expansion
mostly took place at the expense of barren lands. The urban landscape mostly depicts dispersive
outward growth, with a significant amount of compaction near the city core in recent years. The
results derived through Shannon’s Entropy, various Spatial Metrics, and urban density gradient
analysis also indicated the same. The urbanization is higher in Kochi (from 1990 to 2023), while
the projected rate is higher in the case of Mumbai (from 2024 to 2035). The rainfall and
temperature climatological trends indicate that there is no significant rainfall pattern for any of
the cities, with Mumbai being the exception, which shows a rising trend. The future trend
(realized through ConvLSTM model) is projected to be unaltered except for Vishakhapatnam,
where it is expected to increase in the coming years. The average temperature across all cities
depict an increasing trend. For Mumbai and Vishakhapatnam, however, the "increasing trend" is
anticipated to become a "no significant trend" by 2035. Besides, the other factors that are
impacted by urbanization include surface urban heat island, PM2.5, aerosol optical depth, etc.
The DL model-based forecast, therefore, indicates a continuation of urban expansion, which is
expected to have a significant impact on local weather and climate, including rainfall and
temperature trends.