Afforestation in Response to Thermal Change in the Forest-Savannah Transition of the Lamto Scientific Reserve, Côte d'Ivoire
Yıl 2021,
Cilt: 7 Sayı: 2, 45 - 56, 31.12.2021
Kouakou Guy-casımır Douffı
,
Akoua Clementıne Yao
Kouao Jean Koffı
Amara Sıdıkı Traore
Moussa Kone
Öz
In a context of deforestation and climate change, the land cover or use induced by human or natural transformation influences the climate from global to local scale. The aim of this study was to assess the vegetation dynamic between 1985 and 2020 within the Lamto Scientific Reserve (Côte d’Ivoire). After mapping the land cover by the neural network algorithm for the years 1988, 2002 and 2020, the climatic parameters including the Land Surface Temperature (LST) and the standardized precipitation index (SPI) were estimated since 1985. Then, the land cover response was estimated in the presence of the LST, with the average LST from 1985 to 2020 as a threshold. The forest dynamic showed an increase in area of 291.87 ha in 32 years. The area of forest has increased from 610.42 ha (21.42%) in 1988 to 902.29 ha (31.59%) in 2020. The practice of fire remains predominant in the reserve management. SPI shows three alternating seasons over the time. One wet season (1995 to 2010) framed by two dry seasons (1985 to 1994 and 2011 to 2020). The relation LST -NDVI shows covariation. LST indicates a variation from 30.46°C to 34.68°C, with an increase of 4.22°C between 1985 and 2020. The land cover response indicates that, with the exception of the LST of shrub savannahs and burnt areas, the land cover LST of 1988 and 2002 have remained below the LST threshold (32.70°C). The land cover LST of 2020 has risen above the threshold. Land-use changes have led to afforestation despite warming due to bushfires. In addition, forests could continue to act as a thermal moderator of Lamto reserve.
Destekleyen Kurum
UNIVERSITE NANGUI ABROGOUA
Teşekkür
The authors would like to thank the Centre for Ecological Research (CRE) for providing the meteorological data from Lamto. We would also like to thank the United State Geological Survey (USGS) for providing satellite data.
Kaynakça
- Land Use/Land Cover Changes and the Relationship with Land Surface Temperature Using Landsat and MODIS Imageries in Cameron Highlands, Malaysia. Land, 9(372), doi:10.3390/land9100372.
- Anbazhagan, S., Paramasivam, C.R. 2016. Statistical correlation between Land Surface Temperature (LST) and Vegetation Index (NDVI) using multi-temporal Landsat TM data. International Journal of Advanced Earth Science and Engineering 5(1): 333-346.
- Arora, V.K., Montenegro, A. 2011. Small temperature benefits provided by realistic afforestation efforts. Nat Geosci, 4(8): 514-518.
- Barnieh, B.A., Jia, L., Menenti, M., Zhou, J., Zeng, Y. 2020. Mapping Land Use Land Cover Transitions at Different Spatiotemporal Scales in West Africa. Sustainability, 12(8565), doi:10.3390/su12208565.
- Barry, A.A., Caesar, J., Klein Tank, A.M.G., Aguilar, E., McSweeney, C., Cyrille, A.M., Nikiema, M.P., Narcisse, K.B., Sima, F., Stafford, G., Touray, L.M., Ayilari-Naa, J.A., Mendes, C.L., Tounkara, M., Gar-Glahn, E.V.S., Coulibaly, M.S., Dieh, M.F., Mouhaimouni, M., Oyegade, J.A., Samboup, E., Laogbessi, E.T. 2018. West Africa climate extremes and climate change indices. International Journal Of Climatology, DOI: 10.1002/joc.5420.
- Barsi, J.A., Schott, J.R., Hook, S.J., Raqueno, N.G., Markham, B.L., Radocinski, R.G. 2014. Landsat-8 thermal infrared sensor (TIRS) vicarious radiometric calibration. Remote Sensing 6: 11607-11626.
- Buyadi, S.N.A., Mohd, W.M.N.W., Misni, A. 2013. Impact of land use changes on the surface temperature distribution of area surrounding the National Botanic Garden, Shah Alam. Procedia - Social and Behavioral Sciences, 101:516 – 525.
- Cassou, C., Guilyardi, É. 2007. Modes de variabilité et changement climatique: Synthèse du quatrième rapport d’évaluation du Giec. La Météorologie - n° 59 - novembre 2007, 22-30.
- Coulibaly, L., Kouassi, K.H., Soro, G.E., Savané, I. 2016. Analyse du processus de savanisation du Nord de la Côte d’Ivoire par télédétection: Cas du département de Ferkessédougou International Journal of Innovation and Applied Studies, 17(1):136-143.
- Diawara, A., Yoroba, F., Kouadio, K. Y., Kouassi, K. B., Assamoi, E. M., Diedhiou, A., Assamoi, P. 2014. Climate variability in the soudano-Guinean transition area and it impact on vegetation: the case of yhe Lamto region in Côte d'Ivoire. Advances in Meteorology, 11p.
- Do, T.P.T. 2014. Apport de la télédétection spatiale pour l'étude multiscalaire des interactions climat-surface en Afrique de l'Ouest : Etude du bassin verssant de Ouémé supérieur (Bénin). Laboratoire d'étude des trransfert en hydrologie et environnement. Doctorat en science de la terre, de l'univers et de l'environnement, 216 p.
- Douffi, K.G.-C. 2020. Distribution spatiale et dynamique de la population de palmiers rôniers, Borassus aethiopum Mart., par approche de la télédétection et du Système d’Information Géographique (SIG) de la réserve de Lamto (Centre de la Côte d’Ivoire). Biodiversité et Écologie. Université Nangui Abrogoua, Abidjan (Côte d'Ivoire), 2020. Français. ⟨tel-03293386v1⟩
- Douffi, K.G.-C., Koné, M., Kouassi, K.I., N'Guessan, Y. J., Bakayoko, A. 2019. Farmers Establishment Impact on the Forest Dynamic of Monogaga Protected Forest, in the Southwest of Côte d'Ivoire: Remote Sensing and Geographical Information Systems (GIS) Approach. European Journal of Engineering Research and Science, 4(5): 12-20.
- Douffi, K.G.-C., Koné, M., Traoré, A.S., Kouakou, A.A. F., N’guessan, J. 2018. Influence des facteurs environnementaux sur la structure spatiale du peuplement rôniers (Borassus aethiopum Mart.) de la savane, au Centre de la Côte d’Ivoire. International Journal of Engineering Science Invention, 7(6): 40-56
- Gessner, U., Knauer, K., Kuenzer, C., Dech, S. 2015. Land surface phenology in a West African Savanna: impact of land use, land cover and fire. In Remote Sensing Time Series, 203-223. Springer, Cham.
- GIEC. 2014. Changements climatiques 2014: Rapport de synthèse. Contribution des Groupes de travail I, II et III au cinquième Rapport d’évaluation du Groupe d’experts intergouvernemental sur l’évolution du climat [Sous la direction de l’équipe de rédaction principale, R.K. Pachauri et L.A. Meyer]. GIEC, Genève, Suisse, 161 p.
Haylemariyam, M.B. 2018. Detection of Land Surface Temperature in Relation to Land Use Land Cover Change: Dire Dawa City, Ethiopia. J Remote Sens GIS 7: 245. doi:10.4172/2469-4134.1000245.
- Hepner, G.F. 1990. Artificial Neural Network Classification Using a Minimal Training Set: Comparison to Conventional Supervised Classification. Photogrammetric Engineering and Remote Sensing, 56(4): 469-473.
- Huang, J., Zhang, C., Prospero, J. M. 2009. African aerosol and large-scale precipitation variability over West Africa. Environmental Research Letter, 4, 015006 (8pp). doi:10.1088/1748-9326/4/1/015006.
- Jofack Sokeng, V.-C., Kouamé, F.K., Dibi N’da, H., Tankoano, B., Akpa You, L., Ngounou Ngatcha, B. 2016. Cartographie de l’occupation de sol des Hauts Plateaux de l’Ouest Cameroun par réseaux de neurones appliqués à une image LANDSAT 8 OLI. International Journal of Innovation and Scientific Research, 23(2): 443-454.
- Kouamé, K.R., Dibi Kangah, P.A., Koli Bi, Z. 2019. Variabilité climatique dans le centre-est de la Côte d’Ivoire : indicateurs, scénarii actuels et futurs. Revue de Géographie Tropicale et d’Environnement, 1:7-20.
- Koulibaly, A., Kouamé, D., Groga, N., Kouassi, K.E., Bakayoko, A., Porembski, S. 2016. Floristic characteristics of the mosaic and how forest progress on savanna in the Lamto reserve region (Côte d’Ivoire)? International Journal of Development Research, 6(5): 7792-7799.
- Liu, Z., Wimberly, M.C., Dwomoh, F.K. 2017. Vegetation Dynamics in the Upper Guinean Forest Region of West Africa from 2001 to 2015. Remote Sensing, 9(5), doi:10.3390/rs9010005.
- Mckee, T.B., Doedken, N.J., Kleist, J. 1993. The relationship of drought frequency and duration to time scales. In Proceedings of the 8th Conference on Applied Climatology, Vol. 17(22): 179-183). Boston , MA: American Meteorological Society.
- Mobio, A.B.H., Dré, K.F., Kouamé, A.K.D., Djagoua, M.E.V., Affian, K. 2017. Contribution De La Télédétection A L’étude De La Distribution Spatiale De La Température En Fonction Du Relief Et Du Mode D’occupation Du Sol : Cas De La Ville d’Abidjan (Côte d’Ivoire). International Journal of Engineering Science Invention, 6(12): 48-55.
- Morshed, S.R., Fattah, M.A., Rimi, A.A., Haque, M.N. 2020. Surface temperature dynamics in response to land cover transformation. Journal of Civil Engineering, Science and Technology, 11(2).
- N’Datchoh, E.T., Konaré, A., Diedhiou, A., Diawara, A., Quansah, E., Assamoi, P. 2015. Effects of climate variability on savannah fire regimes in West Africa. Earth Syst. Dynam., 6, 161-174. doi:10.5194/esd-6-161-2015.
- N’Dri, A.B., Gignoux, J., Dembele, A., Konate, S. 2012. Short term effects of fire intensity and fire regime on vegetation dynamic in a tropical humid savanna (Lamto, central Côte d’Ivoire) Natural Science, 4(12): 1056-1064.
- Ndossi, I.M., Avdan, U. 2016. Application of open source coding technologies in the production of land surface temperature (LST) maps from Landsat: a PyQGIS plugin. Remote sensing, 8(5):413.
- NourEldeen, N., Mao, K., Yuan, Z., Shen, X., Xu, T., Qin, Z. 2020. Analysis of the Spatiotemporal Change in Land Surface Temperature for a Long Term Sequence in Africa (2003–2017). Remote Sensing, 12, 488. doi:10.3390/rs12030488.
- Odindi, J.O., Nongebeza, S., Siro, N. 2020. The influence of seasonal land-use-land-cover transformation on thermal characteristics within the city of Pietermaritzburg. South African Journal of Geomatics, 9(2):348-360. DOI: http://dx.doi.org/ 10.4314/sajg.v9i2.23.
- OIPR, 2021. Office Ivoirien des Parcs et Réserves : Reserve de Lamto. Consulté le 04/10/2021, Disponible sur https://www.oipr.ci/index.php/parcs-reserves/reserves-naturelles/reserve-de-lamto.
- Oguz, H. 2013. LST calculator: A program for retrieving Land Surface Temperature from Landsat TM/ETM+imagery. Environmental Engineering and Management Journal, 12(3): 549-555.
- Pontius, R. G. 2000. Quantification error versus location in comparison of categorical maps. Photogrammetric Engineering and Remote Sensing, 66(8): 1011 - 1016.
- Qin, Z., Karnieli, A., Berliner, P. 2001. A mono-window algorithm for retrieving land surface temperature from Landsat TM data and its application to the Israel-Egypt border region. International Journal of Remote sensing, 22(18): 3719 - 3746.
- Sekertekin, A., Kutoglu, S.H., Kaya, S., Marangoz, A.M. 2015. Analysing the effects of different land cover types on land surface temperature using satellite data. Remote Sensing & Photogrammetry, International Conference on Sensors & Models in Remote Sensing & Photogrammetry, 23–25 Nov 2015, Kish Island, Iran.
- Setturu, B., Rajan, K.S., Ramachandra, T.V. 2013. Land Surface Temperature Responses to Land Use Land Cover Dynamics. Geoinformatics & Geostatistics: An Overview, 1(4), http://dx.doi.org/10.4172/2327-4581.1000112.
- Tomlinson, C.J., Chapman, L., Thornes, J.E., Baker, C. 2011. Remote sensing land surface temperature for meteorology and climatology: a review. Meteorological Applications, 18, 296-306. DOI: 10.1002/met.287.
- USGS. 2014. Using the USGS Landsat 8 Product. Available online : http://landsat.usgs.gov/Landsat8_Using_Product.php (accessed on 9 November 2014).
- Vlassova, L., Pérez-Cabello, F. 2016. Effects of post-fire wood management strategies on vegetation recovery and land surface temperature (LST) estimated from Landsat images. International Journal of Applied Earth Observation and Geoinformation, 44: 171-183. http://dx.doi.org/10.1016/j.jag.2015.08.011.
- Zhang, J., Wang, Y., Li, Y. 2006. A C++ program for retrieving land surface temperature from the data of landsat TM/ETM+ band 6. Comput. Geosci., 32: 1796-1805.
Yıl 2021,
Cilt: 7 Sayı: 2, 45 - 56, 31.12.2021
Kouakou Guy-casımır Douffı
,
Akoua Clementıne Yao
Kouao Jean Koffı
Amara Sıdıkı Traore
Moussa Kone
Kaynakça
- Land Use/Land Cover Changes and the Relationship with Land Surface Temperature Using Landsat and MODIS Imageries in Cameron Highlands, Malaysia. Land, 9(372), doi:10.3390/land9100372.
- Anbazhagan, S., Paramasivam, C.R. 2016. Statistical correlation between Land Surface Temperature (LST) and Vegetation Index (NDVI) using multi-temporal Landsat TM data. International Journal of Advanced Earth Science and Engineering 5(1): 333-346.
- Arora, V.K., Montenegro, A. 2011. Small temperature benefits provided by realistic afforestation efforts. Nat Geosci, 4(8): 514-518.
- Barnieh, B.A., Jia, L., Menenti, M., Zhou, J., Zeng, Y. 2020. Mapping Land Use Land Cover Transitions at Different Spatiotemporal Scales in West Africa. Sustainability, 12(8565), doi:10.3390/su12208565.
- Barry, A.A., Caesar, J., Klein Tank, A.M.G., Aguilar, E., McSweeney, C., Cyrille, A.M., Nikiema, M.P., Narcisse, K.B., Sima, F., Stafford, G., Touray, L.M., Ayilari-Naa, J.A., Mendes, C.L., Tounkara, M., Gar-Glahn, E.V.S., Coulibaly, M.S., Dieh, M.F., Mouhaimouni, M., Oyegade, J.A., Samboup, E., Laogbessi, E.T. 2018. West Africa climate extremes and climate change indices. International Journal Of Climatology, DOI: 10.1002/joc.5420.
- Barsi, J.A., Schott, J.R., Hook, S.J., Raqueno, N.G., Markham, B.L., Radocinski, R.G. 2014. Landsat-8 thermal infrared sensor (TIRS) vicarious radiometric calibration. Remote Sensing 6: 11607-11626.
- Buyadi, S.N.A., Mohd, W.M.N.W., Misni, A. 2013. Impact of land use changes on the surface temperature distribution of area surrounding the National Botanic Garden, Shah Alam. Procedia - Social and Behavioral Sciences, 101:516 – 525.
- Cassou, C., Guilyardi, É. 2007. Modes de variabilité et changement climatique: Synthèse du quatrième rapport d’évaluation du Giec. La Météorologie - n° 59 - novembre 2007, 22-30.
- Coulibaly, L., Kouassi, K.H., Soro, G.E., Savané, I. 2016. Analyse du processus de savanisation du Nord de la Côte d’Ivoire par télédétection: Cas du département de Ferkessédougou International Journal of Innovation and Applied Studies, 17(1):136-143.
- Diawara, A., Yoroba, F., Kouadio, K. Y., Kouassi, K. B., Assamoi, E. M., Diedhiou, A., Assamoi, P. 2014. Climate variability in the soudano-Guinean transition area and it impact on vegetation: the case of yhe Lamto region in Côte d'Ivoire. Advances in Meteorology, 11p.
- Do, T.P.T. 2014. Apport de la télédétection spatiale pour l'étude multiscalaire des interactions climat-surface en Afrique de l'Ouest : Etude du bassin verssant de Ouémé supérieur (Bénin). Laboratoire d'étude des trransfert en hydrologie et environnement. Doctorat en science de la terre, de l'univers et de l'environnement, 216 p.
- Douffi, K.G.-C. 2020. Distribution spatiale et dynamique de la population de palmiers rôniers, Borassus aethiopum Mart., par approche de la télédétection et du Système d’Information Géographique (SIG) de la réserve de Lamto (Centre de la Côte d’Ivoire). Biodiversité et Écologie. Université Nangui Abrogoua, Abidjan (Côte d'Ivoire), 2020. Français. ⟨tel-03293386v1⟩
- Douffi, K.G.-C., Koné, M., Kouassi, K.I., N'Guessan, Y. J., Bakayoko, A. 2019. Farmers Establishment Impact on the Forest Dynamic of Monogaga Protected Forest, in the Southwest of Côte d'Ivoire: Remote Sensing and Geographical Information Systems (GIS) Approach. European Journal of Engineering Research and Science, 4(5): 12-20.
- Douffi, K.G.-C., Koné, M., Traoré, A.S., Kouakou, A.A. F., N’guessan, J. 2018. Influence des facteurs environnementaux sur la structure spatiale du peuplement rôniers (Borassus aethiopum Mart.) de la savane, au Centre de la Côte d’Ivoire. International Journal of Engineering Science Invention, 7(6): 40-56
- Gessner, U., Knauer, K., Kuenzer, C., Dech, S. 2015. Land surface phenology in a West African Savanna: impact of land use, land cover and fire. In Remote Sensing Time Series, 203-223. Springer, Cham.
- GIEC. 2014. Changements climatiques 2014: Rapport de synthèse. Contribution des Groupes de travail I, II et III au cinquième Rapport d’évaluation du Groupe d’experts intergouvernemental sur l’évolution du climat [Sous la direction de l’équipe de rédaction principale, R.K. Pachauri et L.A. Meyer]. GIEC, Genève, Suisse, 161 p.
Haylemariyam, M.B. 2018. Detection of Land Surface Temperature in Relation to Land Use Land Cover Change: Dire Dawa City, Ethiopia. J Remote Sens GIS 7: 245. doi:10.4172/2469-4134.1000245.
- Hepner, G.F. 1990. Artificial Neural Network Classification Using a Minimal Training Set: Comparison to Conventional Supervised Classification. Photogrammetric Engineering and Remote Sensing, 56(4): 469-473.
- Huang, J., Zhang, C., Prospero, J. M. 2009. African aerosol and large-scale precipitation variability over West Africa. Environmental Research Letter, 4, 015006 (8pp). doi:10.1088/1748-9326/4/1/015006.
- Jofack Sokeng, V.-C., Kouamé, F.K., Dibi N’da, H., Tankoano, B., Akpa You, L., Ngounou Ngatcha, B. 2016. Cartographie de l’occupation de sol des Hauts Plateaux de l’Ouest Cameroun par réseaux de neurones appliqués à une image LANDSAT 8 OLI. International Journal of Innovation and Scientific Research, 23(2): 443-454.
- Kouamé, K.R., Dibi Kangah, P.A., Koli Bi, Z. 2019. Variabilité climatique dans le centre-est de la Côte d’Ivoire : indicateurs, scénarii actuels et futurs. Revue de Géographie Tropicale et d’Environnement, 1:7-20.
- Koulibaly, A., Kouamé, D., Groga, N., Kouassi, K.E., Bakayoko, A., Porembski, S. 2016. Floristic characteristics of the mosaic and how forest progress on savanna in the Lamto reserve region (Côte d’Ivoire)? International Journal of Development Research, 6(5): 7792-7799.
- Liu, Z., Wimberly, M.C., Dwomoh, F.K. 2017. Vegetation Dynamics in the Upper Guinean Forest Region of West Africa from 2001 to 2015. Remote Sensing, 9(5), doi:10.3390/rs9010005.
- Mckee, T.B., Doedken, N.J., Kleist, J. 1993. The relationship of drought frequency and duration to time scales. In Proceedings of the 8th Conference on Applied Climatology, Vol. 17(22): 179-183). Boston , MA: American Meteorological Society.
- Mobio, A.B.H., Dré, K.F., Kouamé, A.K.D., Djagoua, M.E.V., Affian, K. 2017. Contribution De La Télédétection A L’étude De La Distribution Spatiale De La Température En Fonction Du Relief Et Du Mode D’occupation Du Sol : Cas De La Ville d’Abidjan (Côte d’Ivoire). International Journal of Engineering Science Invention, 6(12): 48-55.
- Morshed, S.R., Fattah, M.A., Rimi, A.A., Haque, M.N. 2020. Surface temperature dynamics in response to land cover transformation. Journal of Civil Engineering, Science and Technology, 11(2).
- N’Datchoh, E.T., Konaré, A., Diedhiou, A., Diawara, A., Quansah, E., Assamoi, P. 2015. Effects of climate variability on savannah fire regimes in West Africa. Earth Syst. Dynam., 6, 161-174. doi:10.5194/esd-6-161-2015.
- N’Dri, A.B., Gignoux, J., Dembele, A., Konate, S. 2012. Short term effects of fire intensity and fire regime on vegetation dynamic in a tropical humid savanna (Lamto, central Côte d’Ivoire) Natural Science, 4(12): 1056-1064.
- Ndossi, I.M., Avdan, U. 2016. Application of open source coding technologies in the production of land surface temperature (LST) maps from Landsat: a PyQGIS plugin. Remote sensing, 8(5):413.
- NourEldeen, N., Mao, K., Yuan, Z., Shen, X., Xu, T., Qin, Z. 2020. Analysis of the Spatiotemporal Change in Land Surface Temperature for a Long Term Sequence in Africa (2003–2017). Remote Sensing, 12, 488. doi:10.3390/rs12030488.
- Odindi, J.O., Nongebeza, S., Siro, N. 2020. The influence of seasonal land-use-land-cover transformation on thermal characteristics within the city of Pietermaritzburg. South African Journal of Geomatics, 9(2):348-360. DOI: http://dx.doi.org/ 10.4314/sajg.v9i2.23.
- OIPR, 2021. Office Ivoirien des Parcs et Réserves : Reserve de Lamto. Consulté le 04/10/2021, Disponible sur https://www.oipr.ci/index.php/parcs-reserves/reserves-naturelles/reserve-de-lamto.
- Oguz, H. 2013. LST calculator: A program for retrieving Land Surface Temperature from Landsat TM/ETM+imagery. Environmental Engineering and Management Journal, 12(3): 549-555.
- Pontius, R. G. 2000. Quantification error versus location in comparison of categorical maps. Photogrammetric Engineering and Remote Sensing, 66(8): 1011 - 1016.
- Qin, Z., Karnieli, A., Berliner, P. 2001. A mono-window algorithm for retrieving land surface temperature from Landsat TM data and its application to the Israel-Egypt border region. International Journal of Remote sensing, 22(18): 3719 - 3746.
- Sekertekin, A., Kutoglu, S.H., Kaya, S., Marangoz, A.M. 2015. Analysing the effects of different land cover types on land surface temperature using satellite data. Remote Sensing & Photogrammetry, International Conference on Sensors & Models in Remote Sensing & Photogrammetry, 23–25 Nov 2015, Kish Island, Iran.
- Setturu, B., Rajan, K.S., Ramachandra, T.V. 2013. Land Surface Temperature Responses to Land Use Land Cover Dynamics. Geoinformatics & Geostatistics: An Overview, 1(4), http://dx.doi.org/10.4172/2327-4581.1000112.
- Tomlinson, C.J., Chapman, L., Thornes, J.E., Baker, C. 2011. Remote sensing land surface temperature for meteorology and climatology: a review. Meteorological Applications, 18, 296-306. DOI: 10.1002/met.287.
- USGS. 2014. Using the USGS Landsat 8 Product. Available online : http://landsat.usgs.gov/Landsat8_Using_Product.php (accessed on 9 November 2014).
- Vlassova, L., Pérez-Cabello, F. 2016. Effects of post-fire wood management strategies on vegetation recovery and land surface temperature (LST) estimated from Landsat images. International Journal of Applied Earth Observation and Geoinformation, 44: 171-183. http://dx.doi.org/10.1016/j.jag.2015.08.011.
- Zhang, J., Wang, Y., Li, Y. 2006. A C++ program for retrieving land surface temperature from the data of landsat TM/ETM+ band 6. Comput. Geosci., 32: 1796-1805.