TY  - JOUR
A1  - Heinemann, Sascha
A1  - Siegmann, Bastian
A1  - Thonfeld, Frank
A1  - Muro, Javier
A1  - Jedmowski, Christoph
A1  - Kemna, Andreas
A1  - Kraska, Thorsten
A1  - Muller, Onno
A1  - Schultz, Johannes
A1  - Udelhoven, Thomas
A1  - Wilke, Norman
A1  - Rascher, Uwe
T1  - Land surface temperature retrieval for agricultural areas using a novel UAV platform equipped with a thermal infrared and multispectral sensor
JF  - Remote Sensing
N2  - Land surface temperature (LST) is a fundamental parameter within the system of the Earth’s surface and atmosphere, which can be used to describe the inherent physical processes of energy and water exchange. The need for LST has been increasingly recognised in agriculture, as it affects the growth phases of crops and crop yields. However, challenges in overcoming the large discrepancies between the retrieved LST and ground truth data still exist. Precise LST measurement depends mainly on accurately deriving the surface emissivity, which is very dynamic due to changing states of land cover and plant development. In this study, we present an LST retrieval algorithm for the combined use of multispectral optical and thermal UAV images, which has been optimised for operational applications in agriculture to map the heterogeneous and diverse agricultural crop systems of a research campus in Germany (April 2018). We constrain the emissivity using certain NDVI thresholds to distinguish different land surface types. The algorithm includes atmospheric corrections and environmental thermal emissions to minimise the uncertainties. In the analysis, we emphasise that the omission of crucial meteorological parameters and inaccurately determined emissivities can lead to a considerably underestimated LST; however, if the emissivity is underestimated, the LST can be overestimated. The retrieved LST is validated by reference temperatures from nearby ponds and weather stations. The validation of the thermal measurements indicates a mean absolute error of about 0.5 K. The novelty of the dual sensor system is that it simultaneously captures highly spatially resolved optical and thermal images, in order to construct the precise LST ortho-mosaics required to monitor plant diseases and drought stress and validate airborne and satellite data.
KW  - UAV
KW  - thermal infrared
KW  - multispectral VNIR
KW  - LST
KW  - emissivity
KW  - NDVI thresholds
KW  - atmospheric correction
KW  - agricultural mapping
KW  - low-cost applications
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203557
SN  - 2072-4292
VL  - 12
IS  - 7
ER  - 
TY  - JOUR
A1  - Timmermans, Wim J.
A1  - van der Tol, Christiaan
A1  - Timmermans, Joris
A1  - Ucer, Murat
A1  - Chen, Xuelong
A1  - Alonso, Luis
A1  - Moreno, Jose
A1  - Carrara, Arnaud
A1  - Lopez, Ramon
A1  - Fernando de la Cruz, Tercero
A1  - Corcoles, Horacio L.
A1  - de Miguel, Eduardo
A1  - Sanchez, Jose A. G.
A1  - Perez, Irene
A1  - Belen, Perez
A1  - Munoz, Juan-Carlos J.
A1  - Skokovic, Drazen
A1  - Sobrino, Jose
A1  - Soria, Guillem
A1  - MacArthur, Alasdair
A1  - Vescovo, Loris
A1  - Reusen, Ils
A1  - Andreu, Ana
A1  - Burkart, Andreas
A1  - Cilia, Chiara
A1  - Contreras, Sergio
A1  - Corbari, Chiara
A1  - Calleja, Javier F.
A1  - Guzinski, Radoslaw
A1  - Hellmann, Christine
A1  - Herrmann, Ittai
A1  - Kerr, Gregoire
A1  - Lazar, Adina-Laura
A1  - Leutner, Benjamin
A1  - Mendiguren, Gorka
A1  - Nasilowska, Sylwia
A1  - Nieto, Hector
A1  - Pachego-Labrador, Javier
A1  - Pulanekar, Survana
A1  - Raj, Rahul
A1  - Schikling, Anke
A1  - Siegmann, Bastian
A1  - von Bueren, Stefanie
A1  - Su, Zhongbo (Bob)
T1  - An Overview of the Regional Experiments for Land-atmosphere Exchanges 2012 (REFLEX 2012) Campaign
JF  - Acta Geophysica
N2  - The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites. After presenting the different types of measurements, some examples are given to illustrate the potential of the observations made.
KW  - multi scale heterogeneity
KW  - quantitative remote sensing
KW  - remote
KW  - evapotranspiration
KW  - validation
KW  - issues
KW  - energy
KW  - models
KW  - water
KW  - flux
KW  - land-atmosphere interaction
KW  - turbulence
KW  - calibration and validation
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-136491
VL  - 63
IS  - 6
ER  -