The Oligocene Afro-Arabian flood volcanic province contains significant silicic pyroclastic rocks (】60000 km^3 constituting up to 20%of the volcanic stratigraphy).Rhyolitic tephras,synchronous with the Afro-Arabian s...The Oligocene Afro-Arabian flood volcanic province contains significant silicic pyroclastic rocks (】60000 km^3 constituting up to 20%of the volcanic stratigraphy).Rhyolitic tephras,synchronous with the Afro-Arabian silicic pyroclastic rocks,are found in Indian Ocean ODP holes 711A.They are geoche-mically akin to the Afro-Arabian silicic pyroclastic rocks.This suggests that the tephras originated from Afro-Arabian silicic eruptions and represents more distal fallout of this volcanism.The temporal coin-展开更多
Climate change is described as the most universal and irreversible environmental problem facing the planet Earth. While climate change is already manifesting in Ethiopia through changes in temperature and rainfall, it...Climate change is described as the most universal and irreversible environmental problem facing the planet Earth. While climate change is already manifesting in Ethiopia through changes in temperature and rainfall, its magnitude is poorly studied at regional levels. The objective of this paper was to assess and quantify the magnitude of future changes of climate parameters using Statistical Downscaling Mode (SDSM) version 4.2 in Amhara Regional State which is located between 8°45‘N and 13°45‘N latitude and 35°46‘E and 40°25‘E longitude. Daily climate data (1979- 2008) of rainfall, maximum and minimum temperatures were collected from 10 observed meteorological stations (predictand). The stations were grouped and compared using clustering and Markov chain model, whereas the degree of climate change in the study area was estimated using the coupled HadCM3 general circulation model (GCM) with A2a emission scenarios (Predictors). Both maximum and minimum temperatures showed an increasing trend;the increase in mean maximum temperature ranges between 1.55°C and 6.07°C and that of the mean minimum temperature ranges from 0.11°C and 2.81°C. While the amount of annual rainfall and rainy days decreased in the study Regions in the 2080s. The negative changes in rainfall and temperature obtained from the HadCM3 model in the current study are alarming and suggest the need for further study with several GCM models to confirm the current results and develop adaptation options.展开更多
文摘The Oligocene Afro-Arabian flood volcanic province contains significant silicic pyroclastic rocks (】60000 km^3 constituting up to 20%of the volcanic stratigraphy).Rhyolitic tephras,synchronous with the Afro-Arabian silicic pyroclastic rocks,are found in Indian Ocean ODP holes 711A.They are geoche-mically akin to the Afro-Arabian silicic pyroclastic rocks.This suggests that the tephras originated from Afro-Arabian silicic eruptions and represents more distal fallout of this volcanism.The temporal coin-
文摘Climate change is described as the most universal and irreversible environmental problem facing the planet Earth. While climate change is already manifesting in Ethiopia through changes in temperature and rainfall, its magnitude is poorly studied at regional levels. The objective of this paper was to assess and quantify the magnitude of future changes of climate parameters using Statistical Downscaling Mode (SDSM) version 4.2 in Amhara Regional State which is located between 8°45‘N and 13°45‘N latitude and 35°46‘E and 40°25‘E longitude. Daily climate data (1979- 2008) of rainfall, maximum and minimum temperatures were collected from 10 observed meteorological stations (predictand). The stations were grouped and compared using clustering and Markov chain model, whereas the degree of climate change in the study area was estimated using the coupled HadCM3 general circulation model (GCM) with A2a emission scenarios (Predictors). Both maximum and minimum temperatures showed an increasing trend;the increase in mean maximum temperature ranges between 1.55°C and 6.07°C and that of the mean minimum temperature ranges from 0.11°C and 2.81°C. While the amount of annual rainfall and rainy days decreased in the study Regions in the 2080s. The negative changes in rainfall and temperature obtained from the HadCM3 model in the current study are alarming and suggest the need for further study with several GCM models to confirm the current results and develop adaptation options.
