Copula-based abrupt variations detection in the relationship of seasonal vegetation-climate in the Jing River Basin, China

Understanding the changing relationships between vegetation coverage and precipitation/temperature (P/T) and then exploring their potential drivers are highly necessary for ecosystem management under the backdrop of a changing environment. The Jing River Basin (JRB), a typical eco-environmentally vulnerable region of the Loess Plateau, was chosen to identify abrupt variations of the relationships between seasonal Normalized Difference Vegetation Index (NDVI) and P/T through a copula-based method. By considering the climatic/large-scale atmospheric circulation patterns and human activities, the potential causes of the non-stationarity of the relationship between NDVI and P/T were revealed. Results indicated that (1) the copula-based framework introduced in this study is more reasonable and reliable than the traditional double-mass curves method in detecting change points of vegetation and climate relationships; (2) generally, no significant change points were identified during 1982-2010 at the 95% confidence level, implying the overall stationary relationship still exists, while the relationships between spring NDVI and P/T, autumn NDVI and P have slightly changed; (3) teleconnection factors (including Arctic Oscillation (AO), Pacific Decadal Oscillation (PDO), Nino 3.4, and sunspots) have a more significant influence on the relationship between seasonal NDVI and P/T than local climatic factors (including potential evapotranspiration and soil moisture); (4) negative human activities (expansion of farmland and urban areas) and positive human activities (Grain For Green program) were also potential factors affecting the relationship between NDVI and P/T. This study provides a new and reliable insight into detecting the non-stationarity of the relationship between NDVI and P/T, which will be beneficial for further revealing the connection between the atmosphere and ecosystems

Copula-Based Abrupt Variations Detection in the Relationship of Seasonal Vegetation-Climate in the Jing River Basin, China

Understanding the changing relationships between vegetation coverage and precipitation/temperature (P/T) and then exploring their potential drivers are highly necessary for ecosystem management under the backdrop of a changing environment. The Jing River Basin (JRB), a typical eco-environmentally vulnerable region of the Loess Plateau, was chosen to identify abrupt variations of the relationships between seasonal Normalized Difference Vegetation Index (NDVI) and P/T through a copula-based method. By considering the climatic/large-scale atmospheric circulation patterns and human activities, the potential causes of the non-stationarity of the relationship between NDVI and P/T were revealed. Results indicated that (1) the copula-based framework introduced in this study is more reasonable and reliable than the traditional double-mass curves method in detecting change points of vegetation and climate relationships; (2) generally, no significant change points were identified during 1982–2010 at the 95% confidence level, implying the overall stationary relationship still exists, while the relationships between spring NDVI and P/T, autumn NDVI and P have slightly changed; (3) teleconnection factors (including Arctic Oscillation (AO), Pacific Decadal Oscillation (PDO), Niño 3.4, and sunspots) have a more significant influence on the relationship between seasonal NDVI and P/T than local climatic factors (including potential evapotranspiration and soil moisture); (4) negative human activities (expansion of farmland and urban areas) and positive human activities (“Grain For Green” program) were also potential factors affecting the relationship between NDVI and P/T. This study provides a new and reliable insight into detecting the non-stationarity of the relationship between NDVI and P/T, which will be beneficial for further revealing the connection between the atmosphere and ecosystems

Efecto de la variabilidad atmosférica en la cobertura vegetal del refugio de vida silvestre Laquipampa entre 1990-2020

En la actualidad existen estudios referidos a indicios de variaciones en la cobertura vegetal en ecosistemas frágiles al desequilibrio en las condiciones atmosféricas y el aumento de CO2, es por ello que el presente estudio se plantea el objetivo de determinar el efecto de la variabilidad atmosférica en la cobertura vegetal del Refugio de Vida Silvestre Laquipampa entre 1990-2020, para lo cual fue necesario realizar el análisis de imágenes satelitales mediante el cálculo de NDVI, clasificación supervisada para ser correlacionados mediante RHO de Spearman con datos de las condiciones atmosféricas en el área de estudio de los últimos 30 años, obteniéndose un aumento de 0.05° C/año en la temperatura, 0.6 mm/año en precipitación y un aumento de 30 mil kt de CO2, además se registró la disminución de matorral arbustivo y suelo sin vegetación con tasas de cambio de -0.32 y -0.31. La correlación RHO Spearman se mostró significativa entre la categoría vegetación dispersa/CO2 (0.607), vegetación dispersa/ vapor de agua (0.593) y fuerte entre bosque subhúmedo de montaña/ precipitación (0.786), matorral arbustivo semiárido/ vapor de agua (-0.778), entre otros, lo cual indicó que la variabilidad atmosférica tiene efecto en la cobertura vegetal de manera puntual y discriminada

Efecto de la variabilidad atmosférica en la cobertura vegetal del Refugio de vida silvestre Laquipampa entre 1990-2020

En la actualidad existen estudios referidos a indicios de variaciones en la cobertura vegetal en ecosistemas frágiles al desequilibrio en las condiciones atmosféricas y el aumento de CO2, es por ello que el presente estudio se plantea el objetivo de determinar el efecto de la variabilidad atmosférica en la cobertura vegetal del Refugio de Vida Silvestre Laquipampa entre 1990- 2020, para lo cual fue necesario realizar el análisis de imágenes satelitales mediante el cálculo de NDVI, clasificación supervisada para ser correlacionados mediante RHO de Spearman con datos de las condiciones atmosféricas en el área de estudio de los últimos 30 años, obteniéndose un aumento de 0.05° C/año en la temperatura, 0.6 mm/año en precipitación y un aumento de 30 mil kt de CO2, además se registró la disminución de matorral arbustivo y suelo sin vegetación con tasas de cambio de -0.32 y - 0.31. La correlación RHO Spearman se mostró significativa entre la categoría vegetación dispersa/CO2 (0.607), vegetación dispersa/ vapor de agua (0.593) y fuerte entre bosque subhúmedo de montaña/ precipitación (0.786), matorral arbustivo semiárido/ vapor de agua (-0.778), entre otros, lo cual indicó que la variabilidad atmosférica tiene efecto en la cobertura vegetal de manera puntual y discriminada