Processing of MODIS Vegetation Indices for analysis of agricultural droughts in the southern Ukraine between the years 2000-2012

Abstract

In order to better understand impact of extreme weather events on condition of crop vegetation in Ukraine, analysis of agricultural droughts which occurred in the southern region of Ukraine, between years 2000-2012 was conducted in the current research.

Method of the research
In the current research, the impact of droughts was analyzed on yearly basis by assessing vegetation conditions and comparing it to soil moisture conditions. Normalized difference vegetation index (NDVI) calculated from satellite imagery was used as a proxy for vegetation activity. Soil moisture data was assessed using Temperature Vegetation Dryness Index (TVDI), which provides a way of assessment of soil moisture in relation to temperature of surface acquired by remote sensing. Prior to analysis crop fields with summer and winter crops were classified. Vegetation and climate variables were summarized for each year of the study and statistical analysis functions were applied to in order to assess relations between them. All calculations and data processing operations were automated using the software solutions developed in the course of the research.

Results of the research
A a result of the research statistically significant correlation was found between vegetation conditions and soil moisture over the majority of study area and unusually low vegetation conditions coincided in time with unusually dry surface. Trends were predominantly negative for both amount of soil moisture and vegetation conditions, which may suggest that conditions became drier during the study period and this had negative effects on agriculture. Vast areas of summer crops were affected by unusually dry vegetation conditions in years 2003, 2007 and 2012. Droughts in years 2007, 2009 and 2012 had impact on majority of summer crops planted over the study area.

Relation to previous researches
As in previous researches negative trend was found for vegetation conditions over the study area. The research also approves the occurrence of extreme droughts in years 2003 and 2007. It also complements previous research by finding that winter crops were mostly damaged by droughts in year 2003, while drought in year 2007 has a stronger impact on summer crops. The current research also complements previous approaches of droughts assessment by extending study period till year 2012, which shows abnormal conditions in years 2009 and 2012.

Popular Abstract

Ukrainian agricultural sector plays a significant role in Ukrainian economy. It corresponds to 10% of national GDP and 20% of workforce is employed in the sector. Since the collapse of the Soviet Union, agricultural production has sharply decreased, due to lack of financial resources and pressure of transitions in economy. Currently, there was a steady grows in amount of agricultural productions. However the grows is limited by extreme climate events such as droughts powered by degradation of soils that often result in severe damage of crops on the fields.
Monitoring of droughts requires continues observations over the large areas, which can be efficiently conducted using observations from satellites orbiting the earth with optical sensors on board. In the current research, data sets acquired from satellite imagery were used to assess conditions of vegetation and soil moisture on yearly basis.
By comparison of vegetation activity and soil humidity, it was found that abnormal decrease in amount of water in soils has strong impact on crop vegetation. Severe droughts in years 2003 and 2007 had resulted in damage of crops over vast areas. Less severe droughts in years 2000, 2009, 2012 had also affected conditions of crops. Overall, negative trend was fond for crop conditions and soil moisture, which may suggest that climate in southern Ukraine became drier, which has negative impact on agriculture.
The results of the current research suggest that because of high occurrence of droughts 2-3 years drought mitigation measures shall be planned by farmers as well as crop insurance must be widely used.

• author: Nekrasov, Oleksandr
• supervisor: David Tenenbaum
• organization: Dept of Physical Geography and Ecosystem Science
• alternative title: Monitoring of agricultural droughts in the southern Ukraine using remote sensing
• course: GISM01 20131
• year: 2014
• type: H2 - Master's Degree (Two Years)
• subject: Earth and Environmental Sciences
• keywords: geographic information systems, TVDI, NDVI, agricultural droughts, remote sensing, physical geography and ecosystem analysis, GIS, software development
• publication/series: LUMA-GIS Thesis
• report number: 30
• language: English
• id: 4531725
• date added to LUP: 2014-07-09 11:36:03
• date last changed: 2014-08-27 09:19:47