Time Series Analysis of Landsat Data for Investigating the Relationship between Land Surface Temperature and Forest Changes in Paphos Forest, Cyprus

Vassilis Andronis,Vassilia Karathanassi,Milto Miltiadou,Polychronis Kolokoussis,Chistos Danezis,Victoria Tsalapati

doi:10.3390/rs14041010

Abstract

This study aims to investigate how alternations of the land surface temperature (LST) affects the normalized difference vegetation index (NDVI) in Paphos forest, Cyprus, using Landsat-5 and Landsat-8 imagery for the time periods 1993–2000 and 2013–2018, respectively. A total of 262 Landsat images were processed to compute the mean monthly NDVI and LST values and create a time series. Using the Cook’s distance, the effect of missing values in the analysis of the time series were examined. Results from the cross-correlation and cross-variograms, decomposition model, and the BFAST algorithm were compared to produce reliable conclusions on forest changes and satellite, meteorological, and environmental data were combined to interpret the changes that occurred inside the forest. The decomposition analysis showed a decrease of 2.7% in the LST for the period 1993–2000 and an increase of 4.6% in the LST during the period 2013–2018. The NDVI trend is negatively correlated to the LST trend for both time periods. An increase in the LST trend was identified in November 1998 as well as in the NDVI trend in October 1994 and May 2014 that was caused by favorable climatic conditions. An increase in the NDVI trend from May 2014 to December 2015 may be related to reduced pityocampa attacks. An abrupt decrease was detected in December 2015 that was probably caused by the locust invasion that occurred in the island earlier that year. A positive correlation appears for LST and NDVI variables for time lags 4, 5, 6, 7, and 8 months. Overall, it was shown that LST and NDVI analysis is very promising for identifying potential forest decline.

Highlights

Introduction published maps and institutional affilLand surface temperature (LST) is an important climate related parameter which affects the vegetation and biodiversity in an ecosystem
The composition of forests is changing, so it is important to monitor trends and understand how our forests will be affected in the future by the increase or decrease of the land surface temperature
This is important for advocacy and policy-making, forest preservation, and management

Summary

Introduction

Land surface temperature (LST) is an important climate related parameter which affects the vegetation and biodiversity in an ecosystem. It has, been recognized as an essential environmental factor for monitoring the resilience of our planet [1]. LST affects the partition of energy between the ground and photosynthesizing chlorophyll and determines the surface air temperature [3,4]. It further influences the thermal environment locally [5,6]. Several studies have been conducted to analyze how changes in LST affect the variability of the microclimate of an area, the iations

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