This dataset provides two sets of estimates of soil organic carbon (SOC) and uncertainties as kg ... more This dataset provides two sets of estimates of soil organic carbon (SOC) and uncertainties as kg SOC/m2 in the 0-30 cm topsoil layer at 250-m resolution across Mexico and the conterminous USA (CONUS). The first set of SOC estimates, 1991-2010, were derived using multi-source SOC field data and multiple environmental variables representative of the soil forming environment coupled with a machine learning approach (e.g., simulated annealing) and regression tree ensemble modeling for optimized SOC prediction. Predictions of SOC and uncertainty based on multiple bulk density pedotransfer functions are also included. A second set of SOC estimates and uncertainties, 2009-2011, were derived from two fully independent validation field datasets from across both countries. Note that the same environmental variables and modeling approach as used for the first estimates were applied to these independent datasets for the purpose of assessing the models' sensitivity to multiple SOC data sources. The SOC field data for the first set of estimates are provided and the other data sources are referenced.
... Con contribuciones de: Pablo Martínez 1 , Verónica de la Cruz 1 , Filiberto Jiménez 1 , Omar ... more ... Con contribuciones de: Pablo Martínez 1 , Verónica de la Cruz 1 , Filiberto Jiménez 1 , Omar Masera 4 , René ... Pérez 4 , Adrián Ghilardi 4 , Antonio Ordóñez 5 , Tomás Hernández 5 ... Revisado por: Luis Conde, Aquileo Guzmán y Viridiana Cenyase Albarrán Ramírez Page 2. 2 ...
One of the challenges faced by subwatershed hydrology is the discovery of patterns associated wit... more One of the challenges faced by subwatershed hydrology is the discovery of patterns associated with climate and landscape variability with the available data. This study has three objectives: (1) to evaluate the annual recession curves; (2) to relate the recession parameter (RP) with physiographic characteristics of 21 Mexican subwatersheds in different climate regions; and (3) to formulate a Baseflow (BF) model based on a top-down approach. The RP was calibrated utilizing the largest magnitude curves. The RP was related to topographical, climate and soil variables. A non-linear model was employed to separate the baseflow which considers RP as a recharge rate. Our results show that RP increases with longitude and decreases with latitude. RP displayed a sustained non-linear behavior determined by precipitation rate and evapotranspiration (P E) over years and subwatersheds. The model was fit to a parameter concurrent with invariance and space-time symmetry conditions. The dispersion of our model was associated with the product of (P E) by the aquifer's transmissivity. We put forward a generalized baseflow model, which made the discrimination of baseflow from direct flow in subwatersheds possible. The proposed model involves the recharge-storage-discharge relation and could be implemented in basins where there are no suitable ground-based data.
Ante los retos que plantea la mitigación del cambio climático en el sector AFOLU (agricultura, fo... more Ante los retos que plantea la mitigación del cambio climático en el sector AFOLU (agricultura, forestería y otros usos del suelo), es necesario plantear actividades que, a la vez que disminuyan las emisiones de CO2 a la atmósfera tengan un impacto socio-económico positivo. En Chiapas, el 76% de las emisiones de gases de efecto invernadero están ligadas a las actividades que realizan los productores rurales, por lo cual es fundamental que los tomadores de decisiones cuenten con herramientas sencillas de planeación que les permitan desarrollar actividades y programas de política pública encaminados a contribuir en la resolución de esta problemática. Por otra parte, en el estado, aproximadamente la mitad de las emisiones provienen de los suelos. En este trabajo, mediante análisis cartográfico, se identificaron las principales dinámicas de cambio de uso del suelo en Chiapas entre 2007 y 2011 a nivel regional, las cuales fueron: deforestación de bosques secundarios templados para estable...
El uso de información espectral multi-angular de sensores remotos en plataformas espaciales tiene... more El uso de información espectral multi-angular de sensores remotos en plataformas espaciales tiene el potencial de discriminar clases de coberturas del suelo y otras aplicaciones. En este trabajo se explora el uso de la base del sensor POLDER-1(fuera de operación) en la plataforma ADEOS, el cual permitió obtener hasta 14 mediciones multi-angulares de un mismo pixel. La base de datos fue analizada ajustando un modelo de la función de distribución bidireccional de las reflectancias (BRDF) en las bandas centradas en 443, 565, 670, 765 y 865 micrómetros, para diferentes clases de cobertura del suelo del sistema GLC2000 y así analizar el potencial de usar información multi-angular para discriminar clases de cobertura. Los resultados mostraron los mejores ajustes en las bandas 765 y 865, seguidos por las bandas 565 y 670 y, finalmente, los peores ajustes se dieron en la banda 443. Los errores de ajuste pueden ser interpretados por problemas en la corrección atmosférica asociada a los aeros...
The use of multi-angular spectral information from remote sensors on space platforms has the pote... more The use of multi-angular spectral information from remote sensors on space platforms has the potential to discriminate land cover classes and other applications. In this paper the use of the base of POLDER-1 sensor (non-operating) on ADEOS platform, which yielded up to 14 multi-angular measurements of the same pixel is explored. The database was analyzed by fitting a model of the function of bidirectional reflectance distribution (BRDF) in bands centered at 443, 565, 670, 765 and 865 microns, for different types of ground cover, GLC2000 system, and thus analyze the potential of using multi-angular information to discriminate cover classes. The results showed the best adjustments in the bands 765 and 865, followed by the bands 565 and 670 and, finally, the worst adjustments occurred in the 443 band, were adjustment errors can be interpreted by problems associated with atmospheric correction of tropospheric aerosols (greater effects on the visible bands). With BRDF model adjusted usin...
The nature and size of soil carbon (C) and nitrogen (N) pools and turnover were compared in secon... more The nature and size of soil carbon (C) and nitrogen (N) pools and turnover were compared in secondary and primary forests in a seasonally dry tropical region of Mexico. Total soil C and N, microbial biomass C and N, mineral (ammonium and nitrate) N pools and potential mineralization and nitrification were measured in samples collected during the dry and rainy seasons in early-, mid-, late-successional and primary forests. We hypothesized that the previous agricultural land use of secondary forests would result in lower soil C and N stocks than in primary forest soils, as well as in the seasonal dynamics changes of these two elements. The expected pattern of decreasing soil C and N after a previous agricultural land use did not occur. Soil C was unaffected by the successional stage of the forest. In addition, early-and mid-successional forests registered the highest total and mineral N pools and potential N transformations, whereas primary forests had the lowest N pools and potential cycling. The total soil C and N pools did not change with the sampling season. However, the nitrate pool decreased at the beginning of the rainy season in all forest soils, as did the ammonium pool in primary forests. A striking contrast of the effects of the rainfall (i.e., dry season versus rainy season) seasonality on the microbial biomass and its C:N ratio was observed among forests; latesuccessional and primary forests recorded the lowest values of both parameters at the beginning of the rainy season, whereas early-and mid-successional forests showed the highest values at this sampling date. Therefore, potential N transformations in all forests were the highest during the rainy season. Our study on the consequences of the land cover change on soils, following the discontinuation of agricultural practices, allows us to conclude that the nutrient dynamics in this ecosystem will vary depending on the successional stage of the forests. This work suggests that the full restoration of soil C and N dynamics will take ca. 60 years of secondary succession.
Las emisiones de gases efecto invernadero asociadas al carbono organico del suelo (COS) son impor... more Las emisiones de gases efecto invernadero asociadas al carbono organico del suelo (COS) son importantes para estudiar cambios en los ecosistemas terrestres. Hay modelos simples que, ofrecen la oportunidad de analizar la dinamica de las alteraciones provocadas por los cambios en el uso de suelo, la vegetacion y las practicas de manejo. En Mexico se dispone de informacion del COS total y la textura del suelo. En el presente trabajo se analizan diferentes esquemas para parametrizar el modelo COLPOS, el cual se desarrollo para caracterizar la distribucion del COS en fracciones fisicas del suelo. El modelo considera el COS de diferentes almacenes: materia organica particulada (MOP, materia organica labil) y complejos organominerales (MO + arena-limo-arcilla). El carbono organico inerte (COI), con tiempos medios de residencia de cientos a miles de anos, y el tamano de particula asociado, permiten precisar los parametros del modelo COLPOS y determinar las perdidas potenciales de carbono o...
Red Iberoamericana de Fisica y Quimica Ambiental. Sociedad Iberoamericana de Fisica y Quimica Amb... more Red Iberoamericana de Fisica y Quimica Ambiental. Sociedad Iberoamericana de Fisica y Quimica Ambiental. SiFyQA, Salamanca (2009) Juan F. Gallardo Lancho (Coord.)31 p.
La generacion de escenarios de intervencion para la mitigacion de emisiones es una de las herrami... more La generacion de escenarios de intervencion para la mitigacion de emisiones es una de las herramientas basicas que deben utilizar los gobiernos para desarrollar sus politicas en relacion a la Reduccion de Emisiones en Todos los Usos del Suelo (RETUS), ya que a partir de estos es posible establecer metas de mitigacion y estrategias de actuacion. En Chiapas, a partir de los modelos de estados y transiciones (METs) desarrollados y analisis economico-financiero de las actividades de intervencion se generaron escenarios de mitigacion posibles para REDD+ (Reduccion de Emisiones por Deforestacion y Degradacion forestal) y actividades agropecuarias (AP). En su conjunto, los escenarios REDD+ y AP constituyen el escenario RETUS para Chiapas. El escenario REDD+ planteado abarca un total de 190 Mt CO 2 y casi 2.4 millones de hectareas, mientras que el escenario AP, en su conjunto supone un incremento de casi 48 Mt CO 2 en una superficie de 1.7 millones de hectareas (considerando los almacenes d...
La caracterizacion de la fenologia de la vegetacion, particularmente la asociada a los bosques tr... more La caracterizacion de la fenologia de la vegetacion, particularmente la asociada a los bosques tropicales caducifolios, permite predecir los impactos del cambio climatico y de los intercambios de carbono y agua entre la atmosfera y la vegetacion, por lo que es importante modelarla. Existen diferentes metodos experimentales para caracterizar la fenologia de la vegetacion, sin embargo, el uso de sensores remotos permite caracterizaciones fenologicas de bajo costo y eficientes. No obstante lo anterior, la mayoria de las aplicaciones de sensores remotos cuando se usan indices de vegetacion (IV) solo modelan el crecimiento del follaje (etapa vegetativa y senescente) y no la etapa reproductiva. Dado que la floracion es critica para la viabilidad de la vegetacion, ademas de su valor en la apicultura, es necesario evaluarla con sensores remotos aerotransportados en el segmento visible a infrarrojo del espectro electromagnetico. La revision de experimentos y observaciones de floracion muestr...
Ante los retos que plantea la mitigacion del cambio climatico en el sector AFOLU (agricultura, fo... more Ante los retos que plantea la mitigacion del cambio climatico en el sector AFOLU (agricultura, foresteria y otros usos del suelo), es necesario plantear actividades que, a la vez que disminuyan las emisiones de CO2 a la atmosfera tengan un impacto socio-economico positivo. En Chiapas, el 76% de las emisiones de gases de efecto invernadero estan ligadas a las actividades que realizan los productores rurales, por lo cual es fundamental que los tomadores de decisiones cuenten con herramientas sencillas de planeacion que les permitan desarrollar actividades y programas de politica publica encaminados a contribuir en la resolucion de esta problematica. Por otra parte, en el estado, aproximadamente la mitad de las emisiones provienen de los suelos. En este trabajo, mediante analisis cartograf ico, se identif icaron las principales dinamicas de cambio de uso del suelo en Chiapas entre 2007 y 2011 a nivel regional, las cuales fueron: deforestacion de bosques secundarios templados para estab...
The silt and clay particles play a key role as stabilizing agents of soil organic carbon (SOC). S... more The silt and clay particles play a key role as stabilizing agents of soil organic carbon (SOC). Several lines of evidence indicate a theoretical maximum or C saturation in individual particles. In the present study, we hypothesized that a C fraction displaying linear accumulation relative to the SOC is not influenced by C saturation, while a fraction displaying an asymptotic relationship is regarded as saturated (Stewart et al., 2008). The aim of the present study was to compare the amount of C in the silt and clay sized fractions in temperate and subtropical cropping soils across a range of textures with different mineralogy. Twenty-one and 18 soil samples containing 1:1 and 2:1 clay of temperate soil from Chile under monoculture of maize (Zea maiz L.) for at least 30 years and 9 subtropical soils from Mexico under maize and bean (Phaseolus vulgaris L.) cropping for 9 years having mixed clay were collected at 0-0.1 m. The SOC of 2:1 soils was significantly higher (14±0.5 g kg-1 dry...
A comparison study was performed to evaluate the applicability of optical and SAR data for land c... more A comparison study was performed to evaluate the applicability of optical and SAR data for land cover classification for REDD+ services on a test site in Chiapas State in Mexico. The accuracy of the maps was assessed using an independent data set that was collected from very high resolution optical data. The overall accuracy of the maps varied between 79 % of ENVISAT ASAR and 94 % of RapidEye for the forest – non-forest classifications. The accuracies for the six IPCC compliant classes were from 5 to 9 percentage units lower. Results that were obtained with the optical data were somewhat better than the results using the SAR data. However, the difference between the optical and SAR results was fairly small when L-band SAR data were used. L-band SAR data seem to be competitive alternative for optical data particularly in the areas with frequent cloud cover.
Characterization of vertical distribution of soil organic carbon (SOC) in Mexican soils is an imp... more Characterization of vertical distribution of soil organic carbon (SOC) in Mexican soils is an important task, given the accumulated evidence th...
Using invariant patterns of bare soil and dense vegetation in the red and near infrared space, se... more Using invariant patterns of bare soil and dense vegetation in the red and near infrared space, several approaches for relative atmospheric correction between pairs of satellite images are presented. Methods proposed are reviewed considering temporal changes in the reflectance of bare soil and dense vegetation in short periods of time using radiative transfer simulations. Also, the use of isolines of vegetation, any coberture, is used in a general method to correct the atmospheric effect in satellite images. The methods introduced in this paper are exemplified using radiative simulations with the 6S model, under generic atmosphere profiles. The results of the different approaches are discussed in regards to real applications found in the field
This dataset provides two sets of estimates of soil organic carbon (SOC) and uncertainties as kg ... more This dataset provides two sets of estimates of soil organic carbon (SOC) and uncertainties as kg SOC/m2 in the 0-30 cm topsoil layer at 250-m resolution across Mexico and the conterminous USA (CONUS). The first set of SOC estimates, 1991-2010, were derived using multi-source SOC field data and multiple environmental variables representative of the soil forming environment coupled with a machine learning approach (e.g., simulated annealing) and regression tree ensemble modeling for optimized SOC prediction. Predictions of SOC and uncertainty based on multiple bulk density pedotransfer functions are also included. A second set of SOC estimates and uncertainties, 2009-2011, were derived from two fully independent validation field datasets from across both countries. Note that the same environmental variables and modeling approach as used for the first estimates were applied to these independent datasets for the purpose of assessing the models' sensitivity to multiple SOC data sources. The SOC field data for the first set of estimates are provided and the other data sources are referenced.
... Con contribuciones de: Pablo Martínez 1 , Verónica de la Cruz 1 , Filiberto Jiménez 1 , Omar ... more ... Con contribuciones de: Pablo Martínez 1 , Verónica de la Cruz 1 , Filiberto Jiménez 1 , Omar Masera 4 , René ... Pérez 4 , Adrián Ghilardi 4 , Antonio Ordóñez 5 , Tomás Hernández 5 ... Revisado por: Luis Conde, Aquileo Guzmán y Viridiana Cenyase Albarrán Ramírez Page 2. 2 ...
One of the challenges faced by subwatershed hydrology is the discovery of patterns associated wit... more One of the challenges faced by subwatershed hydrology is the discovery of patterns associated with climate and landscape variability with the available data. This study has three objectives: (1) to evaluate the annual recession curves; (2) to relate the recession parameter (RP) with physiographic characteristics of 21 Mexican subwatersheds in different climate regions; and (3) to formulate a Baseflow (BF) model based on a top-down approach. The RP was calibrated utilizing the largest magnitude curves. The RP was related to topographical, climate and soil variables. A non-linear model was employed to separate the baseflow which considers RP as a recharge rate. Our results show that RP increases with longitude and decreases with latitude. RP displayed a sustained non-linear behavior determined by precipitation rate and evapotranspiration (P E) over years and subwatersheds. The model was fit to a parameter concurrent with invariance and space-time symmetry conditions. The dispersion of our model was associated with the product of (P E) by the aquifer's transmissivity. We put forward a generalized baseflow model, which made the discrimination of baseflow from direct flow in subwatersheds possible. The proposed model involves the recharge-storage-discharge relation and could be implemented in basins where there are no suitable ground-based data.
Ante los retos que plantea la mitigación del cambio climático en el sector AFOLU (agricultura, fo... more Ante los retos que plantea la mitigación del cambio climático en el sector AFOLU (agricultura, forestería y otros usos del suelo), es necesario plantear actividades que, a la vez que disminuyan las emisiones de CO2 a la atmósfera tengan un impacto socio-económico positivo. En Chiapas, el 76% de las emisiones de gases de efecto invernadero están ligadas a las actividades que realizan los productores rurales, por lo cual es fundamental que los tomadores de decisiones cuenten con herramientas sencillas de planeación que les permitan desarrollar actividades y programas de política pública encaminados a contribuir en la resolución de esta problemática. Por otra parte, en el estado, aproximadamente la mitad de las emisiones provienen de los suelos. En este trabajo, mediante análisis cartográfico, se identificaron las principales dinámicas de cambio de uso del suelo en Chiapas entre 2007 y 2011 a nivel regional, las cuales fueron: deforestación de bosques secundarios templados para estable...
El uso de información espectral multi-angular de sensores remotos en plataformas espaciales tiene... more El uso de información espectral multi-angular de sensores remotos en plataformas espaciales tiene el potencial de discriminar clases de coberturas del suelo y otras aplicaciones. En este trabajo se explora el uso de la base del sensor POLDER-1(fuera de operación) en la plataforma ADEOS, el cual permitió obtener hasta 14 mediciones multi-angulares de un mismo pixel. La base de datos fue analizada ajustando un modelo de la función de distribución bidireccional de las reflectancias (BRDF) en las bandas centradas en 443, 565, 670, 765 y 865 micrómetros, para diferentes clases de cobertura del suelo del sistema GLC2000 y así analizar el potencial de usar información multi-angular para discriminar clases de cobertura. Los resultados mostraron los mejores ajustes en las bandas 765 y 865, seguidos por las bandas 565 y 670 y, finalmente, los peores ajustes se dieron en la banda 443. Los errores de ajuste pueden ser interpretados por problemas en la corrección atmosférica asociada a los aeros...
The use of multi-angular spectral information from remote sensors on space platforms has the pote... more The use of multi-angular spectral information from remote sensors on space platforms has the potential to discriminate land cover classes and other applications. In this paper the use of the base of POLDER-1 sensor (non-operating) on ADEOS platform, which yielded up to 14 multi-angular measurements of the same pixel is explored. The database was analyzed by fitting a model of the function of bidirectional reflectance distribution (BRDF) in bands centered at 443, 565, 670, 765 and 865 microns, for different types of ground cover, GLC2000 system, and thus analyze the potential of using multi-angular information to discriminate cover classes. The results showed the best adjustments in the bands 765 and 865, followed by the bands 565 and 670 and, finally, the worst adjustments occurred in the 443 band, were adjustment errors can be interpreted by problems associated with atmospheric correction of tropospheric aerosols (greater effects on the visible bands). With BRDF model adjusted usin...
The nature and size of soil carbon (C) and nitrogen (N) pools and turnover were compared in secon... more The nature and size of soil carbon (C) and nitrogen (N) pools and turnover were compared in secondary and primary forests in a seasonally dry tropical region of Mexico. Total soil C and N, microbial biomass C and N, mineral (ammonium and nitrate) N pools and potential mineralization and nitrification were measured in samples collected during the dry and rainy seasons in early-, mid-, late-successional and primary forests. We hypothesized that the previous agricultural land use of secondary forests would result in lower soil C and N stocks than in primary forest soils, as well as in the seasonal dynamics changes of these two elements. The expected pattern of decreasing soil C and N after a previous agricultural land use did not occur. Soil C was unaffected by the successional stage of the forest. In addition, early-and mid-successional forests registered the highest total and mineral N pools and potential N transformations, whereas primary forests had the lowest N pools and potential cycling. The total soil C and N pools did not change with the sampling season. However, the nitrate pool decreased at the beginning of the rainy season in all forest soils, as did the ammonium pool in primary forests. A striking contrast of the effects of the rainfall (i.e., dry season versus rainy season) seasonality on the microbial biomass and its C:N ratio was observed among forests; latesuccessional and primary forests recorded the lowest values of both parameters at the beginning of the rainy season, whereas early-and mid-successional forests showed the highest values at this sampling date. Therefore, potential N transformations in all forests were the highest during the rainy season. Our study on the consequences of the land cover change on soils, following the discontinuation of agricultural practices, allows us to conclude that the nutrient dynamics in this ecosystem will vary depending on the successional stage of the forests. This work suggests that the full restoration of soil C and N dynamics will take ca. 60 years of secondary succession.
Las emisiones de gases efecto invernadero asociadas al carbono organico del suelo (COS) son impor... more Las emisiones de gases efecto invernadero asociadas al carbono organico del suelo (COS) son importantes para estudiar cambios en los ecosistemas terrestres. Hay modelos simples que, ofrecen la oportunidad de analizar la dinamica de las alteraciones provocadas por los cambios en el uso de suelo, la vegetacion y las practicas de manejo. En Mexico se dispone de informacion del COS total y la textura del suelo. En el presente trabajo se analizan diferentes esquemas para parametrizar el modelo COLPOS, el cual se desarrollo para caracterizar la distribucion del COS en fracciones fisicas del suelo. El modelo considera el COS de diferentes almacenes: materia organica particulada (MOP, materia organica labil) y complejos organominerales (MO + arena-limo-arcilla). El carbono organico inerte (COI), con tiempos medios de residencia de cientos a miles de anos, y el tamano de particula asociado, permiten precisar los parametros del modelo COLPOS y determinar las perdidas potenciales de carbono o...
Red Iberoamericana de Fisica y Quimica Ambiental. Sociedad Iberoamericana de Fisica y Quimica Amb... more Red Iberoamericana de Fisica y Quimica Ambiental. Sociedad Iberoamericana de Fisica y Quimica Ambiental. SiFyQA, Salamanca (2009) Juan F. Gallardo Lancho (Coord.)31 p.
La generacion de escenarios de intervencion para la mitigacion de emisiones es una de las herrami... more La generacion de escenarios de intervencion para la mitigacion de emisiones es una de las herramientas basicas que deben utilizar los gobiernos para desarrollar sus politicas en relacion a la Reduccion de Emisiones en Todos los Usos del Suelo (RETUS), ya que a partir de estos es posible establecer metas de mitigacion y estrategias de actuacion. En Chiapas, a partir de los modelos de estados y transiciones (METs) desarrollados y analisis economico-financiero de las actividades de intervencion se generaron escenarios de mitigacion posibles para REDD+ (Reduccion de Emisiones por Deforestacion y Degradacion forestal) y actividades agropecuarias (AP). En su conjunto, los escenarios REDD+ y AP constituyen el escenario RETUS para Chiapas. El escenario REDD+ planteado abarca un total de 190 Mt CO 2 y casi 2.4 millones de hectareas, mientras que el escenario AP, en su conjunto supone un incremento de casi 48 Mt CO 2 en una superficie de 1.7 millones de hectareas (considerando los almacenes d...
La caracterizacion de la fenologia de la vegetacion, particularmente la asociada a los bosques tr... more La caracterizacion de la fenologia de la vegetacion, particularmente la asociada a los bosques tropicales caducifolios, permite predecir los impactos del cambio climatico y de los intercambios de carbono y agua entre la atmosfera y la vegetacion, por lo que es importante modelarla. Existen diferentes metodos experimentales para caracterizar la fenologia de la vegetacion, sin embargo, el uso de sensores remotos permite caracterizaciones fenologicas de bajo costo y eficientes. No obstante lo anterior, la mayoria de las aplicaciones de sensores remotos cuando se usan indices de vegetacion (IV) solo modelan el crecimiento del follaje (etapa vegetativa y senescente) y no la etapa reproductiva. Dado que la floracion es critica para la viabilidad de la vegetacion, ademas de su valor en la apicultura, es necesario evaluarla con sensores remotos aerotransportados en el segmento visible a infrarrojo del espectro electromagnetico. La revision de experimentos y observaciones de floracion muestr...
Ante los retos que plantea la mitigacion del cambio climatico en el sector AFOLU (agricultura, fo... more Ante los retos que plantea la mitigacion del cambio climatico en el sector AFOLU (agricultura, foresteria y otros usos del suelo), es necesario plantear actividades que, a la vez que disminuyan las emisiones de CO2 a la atmosfera tengan un impacto socio-economico positivo. En Chiapas, el 76% de las emisiones de gases de efecto invernadero estan ligadas a las actividades que realizan los productores rurales, por lo cual es fundamental que los tomadores de decisiones cuenten con herramientas sencillas de planeacion que les permitan desarrollar actividades y programas de politica publica encaminados a contribuir en la resolucion de esta problematica. Por otra parte, en el estado, aproximadamente la mitad de las emisiones provienen de los suelos. En este trabajo, mediante analisis cartograf ico, se identif icaron las principales dinamicas de cambio de uso del suelo en Chiapas entre 2007 y 2011 a nivel regional, las cuales fueron: deforestacion de bosques secundarios templados para estab...
The silt and clay particles play a key role as stabilizing agents of soil organic carbon (SOC). S... more The silt and clay particles play a key role as stabilizing agents of soil organic carbon (SOC). Several lines of evidence indicate a theoretical maximum or C saturation in individual particles. In the present study, we hypothesized that a C fraction displaying linear accumulation relative to the SOC is not influenced by C saturation, while a fraction displaying an asymptotic relationship is regarded as saturated (Stewart et al., 2008). The aim of the present study was to compare the amount of C in the silt and clay sized fractions in temperate and subtropical cropping soils across a range of textures with different mineralogy. Twenty-one and 18 soil samples containing 1:1 and 2:1 clay of temperate soil from Chile under monoculture of maize (Zea maiz L.) for at least 30 years and 9 subtropical soils from Mexico under maize and bean (Phaseolus vulgaris L.) cropping for 9 years having mixed clay were collected at 0-0.1 m. The SOC of 2:1 soils was significantly higher (14±0.5 g kg-1 dry...
A comparison study was performed to evaluate the applicability of optical and SAR data for land c... more A comparison study was performed to evaluate the applicability of optical and SAR data for land cover classification for REDD+ services on a test site in Chiapas State in Mexico. The accuracy of the maps was assessed using an independent data set that was collected from very high resolution optical data. The overall accuracy of the maps varied between 79 % of ENVISAT ASAR and 94 % of RapidEye for the forest – non-forest classifications. The accuracies for the six IPCC compliant classes were from 5 to 9 percentage units lower. Results that were obtained with the optical data were somewhat better than the results using the SAR data. However, the difference between the optical and SAR results was fairly small when L-band SAR data were used. L-band SAR data seem to be competitive alternative for optical data particularly in the areas with frequent cloud cover.
Characterization of vertical distribution of soil organic carbon (SOC) in Mexican soils is an imp... more Characterization of vertical distribution of soil organic carbon (SOC) in Mexican soils is an important task, given the accumulated evidence th...
Using invariant patterns of bare soil and dense vegetation in the red and near infrared space, se... more Using invariant patterns of bare soil and dense vegetation in the red and near infrared space, several approaches for relative atmospheric correction between pairs of satellite images are presented. Methods proposed are reviewed considering temporal changes in the reflectance of bare soil and dense vegetation in short periods of time using radiative transfer simulations. Also, the use of isolines of vegetation, any coberture, is used in a general method to correct the atmospheric effect in satellite images. The methods introduced in this paper are exemplified using radiative simulations with the 6S model, under generic atmosphere profiles. The results of the different approaches are discussed in regards to real applications found in the field
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