An assessment of water reserve changes in Salt Lake, Turkey, through multi‐temporal Landsat imagery and real‐time ground surveys

Abstract

Abstract:This paper focuses mainly on the investigation of water reserve changes in Salt Lake, Turkey, using remote-sensing data. The study is performed in two stages: (1) correlation analysis for real-time ground and satellite data and (2) assessment of water reserve changes using multi-temporal Landsat imagery. First, correlation analysis is conducted to investigate the relationship between digital data from Landsat-5 TM and spectral (in situ) measurements collected using a field spectroradiometer on the same day and time. A radiometric correction procedure, including conversions from digital numbers to radiance and from radiance to at-satellite reflectance, is executed to make satellite data comparable to in situ measurements. This procedure show that simultaneous ground and satellite remote-sensing data are highly correlated (0Ð84 > R 2 > 97) and the near-infrared region (for this study TM4-Landsat-5 TM, band 4) is the best spectral range to distinguish salt and water on the satellite data for the multi-temporal analysis of the water reserve in Salt Lake. It also shows that the use of shortwave infrared band(s) will result in confusion for the determination of the water reserve in this water-covered study area. In a second and last phase, the water reserve change in the lake is examined using multi-temporal Landsat imagery collected in 1990, 2001 and 2005. The remotely sensed, sampled and treated data show that the water reserve in the lake has decreased markedly between 1990 and 2005 due to drought and uncontrolled water usage. It is suggested that the use of water supplies around Salt Lake should be controlled and that the lake should regularly be monitored by up-to-date remote-sensing data (at least annually) for better management of water resources.

Changes in the Coastline and Water Level of the Akşehir and Eber Lakes Between 1975 and 2009

“…The root mean square error of the polynomial transformation was less than half a pixel for the entire dataset. Checkpoints were measured on the geometrically corrected image set and compared with the topographic sheets to evaluate the quality of the geometric correction (Jensen 1996;Ormeci and Ekercin 2007). The delineation and extraction of the coastlines of lakes were mapped using optical and radar imagery in several ways.…”

“…In Turkey, most lake monitoring studies that use remote sensing have been conducted to assess the water level because of changes in climate and human activities such as the Salt Lake (Ormeci and Ekercin 2007), Ulubat Lake (Taǧıl 2007), Seyfe Lake (Reis and Yılmaz 2008) and Akşehir and Eber Lakes (Sener et al 2009). …”

Evaluating climate change effects on water and salt resources in Salt Lake, Turkey using multitemporal SPOT imagery

“…Because Fig. 4 Interpretation of the seasonal and temporal changes in Salt Lake, Turkey by using (almost) the same dated 3-D SPOT pseudocolor images of this, the near-infrared band can only be used to detect the water surface area in Salt Lake due to the low water depth (which is between 1 and 50 cm) and the salt-covered lake bottom (Örmeci and Ekercin 2007). Taking these into account, in this study, water and salt reserve changes in Salt Lake were determined through the near-infrared bands of multitemporal SPOT imagery collected on almost the same days in 1987 and 2005.…”

An Application of Landsat-5TM Image Data for Water Quality Mapping in Lake Beysehir, Turkey

“…Image processing procedures were carried out using Erdas Imagine© and ASD ViewSpecPro© software packages. Additionally, topographic maps in the scale of 1:25,000 were used to get ground control points for the geometric correction process (Örmeci and Ekercin 2007). …”