Student Research Reports

View Research Report

ABSTRACT Normalized Difference Vegetation Index (NDVI) is a remote sensing technology that is used to determine the amount of vegetation cover on the earth’s surface. It is important to determine vegetation cover on the earth’s surface because any changes on vegetation cover affects our health, economy and environment. In an effort to monitor major fluctuations in vegetation and understand how they affect the environment, 20 years ago Earth scientists began using satellite remote sensors to measure and map the density of green vegetation over the Earth. Using NOAA’s Advanced Very High Resolution Radiometer (AVHRR), scientists have been collecting images of our planet’s surface. NDVI is useful for farmers as it helps them monitor and manage their farms remotely, and can predict climate changes such as drought. Since NDVI determines vegetation cover, it can also be correlated with incidences of vector borne diseases such as malaria, which is transmitted by the mosquito. In this study, normalized data from Homa Bay County was used to determine whether there was a correlation between NDVI and malaria occurrence with weather conditions (precipitation, humidity and temperature) in Homa Bay County during the period between January, 2017 and February, 2018. From the results, it was clear that both NDVI and malaria occurrence were highest during the month of May, 2017, which is the peak of the long rainy season in Kenya. The month of May, 2017 recorded the highest precipitation, humidity, malaria occurrence and the moderately high temperature. This month coincides with the growth of the maize crop, one of the most common food crops grown in Homa Bay. Hence, there is high vegetation cover during this month, which also encourages mosquito breeding. The levels of NDVI, precipitation and humidity steadily dropped between June and July 2017. This coincides with the harvesting season, whereby the maize stalks turn yellow in color, causing the NDVI values to drop. The NDVI value peaks again during the short rains, i.e. November, 2019, which also recorded relatively high precipitation and humidity. This coincides with the second growth season for the maize plant. Malaria occurrence was found to be very high during the month of May and November, 2017, when there was high precipitation, high humidity and low temperature. During these months, the NDVI value was at its highest, which means the vegetation cover was very high. High vegetation and warm temperature encourages mosquito breeding, which results in high malaria transmission. Notably the adult female mosquitoes look for vegetation to rest on after laying their eggs- and thus the vegetation is an important variable. NDVI is therefore a promising technology for monitoring vegetation cover, which in turn can provide information on vector borne diseases such as malaria. This information is useful to farmers as it will help to improve productivity.