Claudia Timmreck - Academia.edu (original) (raw)
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Papers by Claudia Timmreck
The interannual and interseasonal variability of natural aerosol components (seasalt and soil dus... more The interannual and interseasonal variability of natural aerosol components (seasalt and soil dust) has been investigated with the climate model ECHAM4. ECHAM4 can be operated in different modes, such as in a nudged mode and in a climatological mode. A big advantage of a nudged simulation is that realistic transport of the aerosol facilitates any comparison to observations, while for climate change experiments the model develops its own meteorology, We have investigated how the geographical distribution and the interannual and seasonal variability of seasalt and mineral dust aerosol change between the different modes of operation of the climate model. Such changes can be a source of error in estimating the climate effect of natural aerosol components. Four experiments have been performed: a climatological with prescribed climatological sea surface temperature (SST), two experiments with prescribed SSTs from the particular years 1986 and 1989 and a nudged experiment where the model is forced by ECMWF Reanalysis data of the years 1986-1991 and corresponding SSTs from each year. Our results indicate that the mode of operation of the climate model seems to be as important as the interannual variability of the natural aerosol component by climate variations alone. The model results have been carefully compared with satellite observations from METEOSAT and with ground based measurements. Special emphasis is placed on the ability of the model to reflect the observed correlation of aerosol distribution with the North Atlantic oscillation, which is a prominent atmospheric variability mode and major reason for interannual variability in aerosol load and transport over the North Atlantic.
Journal of Aerosol Science, Sep 1, 2000
Journal of Geophysical Research Atmospheres, 2001
Journal of Geophysical Research Atmospheres
Meteorologische Zeitschrift
Wiley Interdisciplinary Reviews: Climate Change, 2012
Geophysical Monograph Series, 2000
ABSTRACT
All of the referees' comments have been considered in the paper. One reviewer (D. Stevenson)... more All of the referees' comments have been considered in the paper. One reviewer (D. Stevenson) made suggestions concerning the English. We went carefully over the text and included all suggestions for improving the English. In the following, we will briefly answer to specific points.
Theoretical and Applied Climatology, 1999
Journal of Geophysical Research: Atmospheres, 2001
Journal of Geophysical Research, 2001
Atmospheric Chemistry and Physics, 2006
pa.op.dlr.de
... 197 Particles and Cirrus Clouds (PAZI): Overview of results 2000 - 2003 ... 207 Ice-nucleatin... more ... 197 Particles and Cirrus Clouds (PAZI): Overview of results 2000 - 2003 ... 207 Ice-nucleating ability of soot particles in UT/LS J. Suzanne * ,D. Ferry F. CRMC2-CNRS, Campus de Luminy, Case 913, F-13288 Marseille cedex 9, France ...
The impact of volcanic eruptions on the marine carbon cycle is investigated for the example of th... more The impact of volcanic eruptions on the marine carbon cycle is investigated for the example of the Pinatubo eruption with model simulations of the distribution of the ash cloud and deposition on the ocean surface and the impact of the nutrient addition from ash leachates on the oceanic biological production and hence biological carbon pump. Natural variations of aerosols, especially due to large-magnitude volcanic eruptions, are recognized as a significant climate forcing, altering the Earth's radiation balance and thus tending to cause global temperature changes. While the impact of such events on climate and the terrestrial biosphere is relatively well documented, scientific knowledge of their effects on marine ecosystems and consequent feedbacks to the atmosphere is still very limited. In the deep sea, subaerial eruptive events of global significance are commonly recorded as widespread ash layers, which were often found to be associated with increased abundances of planktic organisms. This has led to the hypothesis that the influx of volcanic ash may provide an external nutrient source for primary production (in particular through iron fertilization) in ocean surface waters. Recent laboratory experiments have demonstrated that pristine volcanic ash indeed releases significant amounts of macronutrients and bioactive trace metals (including phosphate, iron and silica) adsorbed to the surface of the ash particles. The release of these components most likely has its largest impact in ocean regions where their availability is crucial for the growth of oceanic biomass, which are the high-nutrient but low-productivity (low-iron) areas in the Pacific and the Southern Ocean. These in turn are neighbored by most of those subaerially active volcanoes that are capable of ejecting huge amounts of aerosols into the high-velocity stratospheric wind fields. The dispersal and fallout of ash thus has a high potential to induce globally significant, transient net CO2 removal from the upper ocean and hence the atmosphere. Large-magnitude eruptions such as of Mount Pinatubo in 1991 were in fact followed by a slowing-down in the increase of atmospheric CO2 for several years, entailing a weakening of the global warming trend. For Mount Pinatubo it has been argued that the estimated CO2 uptake (1.6 x 1015 g C) could have been caused by rapid iron fertilization of the Southern Ocean with about 6.3 x 1015 g of ash. However, this would approximate the overall amount of the ash generated by the eruption, of which about 80% fell out over the South China Sea (~4.9 x 1015 g). This suggests additional avenues for the removal of CO2, among which the 1991 explosive eruption of Cerro Hudson could have played an important role as more than 2 km3 of the aerosols released by the volcano fell out directly over the Southern Ocean.
Egu General Assembly Conference Abstracts, May 1, 2010
Volcanic aerosols are an active component of the climate system and play multiple roles in physic... more Volcanic aerosols are an active component of the climate system and play multiple roles in physical and biogeochemical exchanges between the atmosphere, land, surface and ocean. To study the influence of volcanic aerosol on atmospheric dynamics and composition, dependent on the geographical latitude, interactive simulations of major volcanic eruptions are required. For our studies we use the middle atmosphere general circulation model MAECHAM5 including the global aerosol module HAM. HAM calculates the aerosol microphysics of sulfate and other species and their source and sink processes. The model setup has been validated for the Pinatubo eruption, showing good agreement with satellite data. Model studies have been performed for different major volcanic eruptions in the tropics and mid and high Northern latitudes (Pinatubo, Vesuvius, Katmai) with the strength and the eruption height of the Pinatubo eruption. All volcanic eruptions have been initialized in Northern Hemisphere summer and calculated for two years. The global distribution of the aerosol optical depth shows that the Pinatubo cloud is distributed over both hemispheres and has a global effect on climate. Volcanic aerosol of the Vesuvius eruption is mostly located in the Northern Hemisphere and has a more hemispheric effect but a certain fraction is also found in the Southern Hemisphere. Similar to the Pinatubo eruption the Vesuvius cloud is distributed fast to the north with the transition from summer to winter circulation. The volcanic aerosol of a Katmai eruption is only found in the Northern Hemisphere between 30°N und 90°N. The atmospheric life time of the volcanic aerosol varies with the geographic latitude of the volcano, Katmai has the shortest life time with 1.5 years and Pinatubo the longest one with 2.5 years. The strongest stratospheric temperature anomalies occur for the Pinatubo eruption in the tropics although chemical feedback mechanism not included in our simulation which might dampen the effect.
In recent years, several methods have been suggested for "geoengineering" the c... more In recent years, several methods have been suggested for "geoengineering" the climate to limit global temperature increase. One of these geoengineering techniques follows the natural example of volcanic eruptions, emitting large amounts of sulfur dioxide (SO2) into the stratosphere. Chemical and microphysical reactions cause the formation of sulfate aerosols, which reduces the incoming solar radiation. Recently, several studies on this
Super eruptions exert an extreme forcing on the Earth System. The emitted volcanic aerosol stays ... more Super eruptions exert an extreme forcing on the Earth System. The emitted volcanic aerosol stays several years in the stratosphere, causing strong radiative effects with consequences for atmospheric processes. The interactive simulation of formation, dispersal and temporal development of a very large volcanic cloud is a challenging task for every aerosol climate model. For our studies we use the middle
The interannual and interseasonal variability of natural aerosol components (seasalt and soil dus... more The interannual and interseasonal variability of natural aerosol components (seasalt and soil dust) has been investigated with the climate model ECHAM4. ECHAM4 can be operated in different modes, such as in a nudged mode and in a climatological mode. A big advantage of a nudged simulation is that realistic transport of the aerosol facilitates any comparison to observations, while for climate change experiments the model develops its own meteorology, We have investigated how the geographical distribution and the interannual and seasonal variability of seasalt and mineral dust aerosol change between the different modes of operation of the climate model. Such changes can be a source of error in estimating the climate effect of natural aerosol components. Four experiments have been performed: a climatological with prescribed climatological sea surface temperature (SST), two experiments with prescribed SSTs from the particular years 1986 and 1989 and a nudged experiment where the model is forced by ECMWF Reanalysis data of the years 1986-1991 and corresponding SSTs from each year. Our results indicate that the mode of operation of the climate model seems to be as important as the interannual variability of the natural aerosol component by climate variations alone. The model results have been carefully compared with satellite observations from METEOSAT and with ground based measurements. Special emphasis is placed on the ability of the model to reflect the observed correlation of aerosol distribution with the North Atlantic oscillation, which is a prominent atmospheric variability mode and major reason for interannual variability in aerosol load and transport over the North Atlantic.
Journal of Aerosol Science, Sep 1, 2000
Journal of Geophysical Research Atmospheres, 2001
Journal of Geophysical Research Atmospheres
Meteorologische Zeitschrift
Wiley Interdisciplinary Reviews: Climate Change, 2012
Geophysical Monograph Series, 2000
ABSTRACT
All of the referees' comments have been considered in the paper. One reviewer (D. Stevenson)... more All of the referees' comments have been considered in the paper. One reviewer (D. Stevenson) made suggestions concerning the English. We went carefully over the text and included all suggestions for improving the English. In the following, we will briefly answer to specific points.
Theoretical and Applied Climatology, 1999
Journal of Geophysical Research: Atmospheres, 2001
Journal of Geophysical Research, 2001
Atmospheric Chemistry and Physics, 2006
pa.op.dlr.de
... 197 Particles and Cirrus Clouds (PAZI): Overview of results 2000 - 2003 ... 207 Ice-nucleatin... more ... 197 Particles and Cirrus Clouds (PAZI): Overview of results 2000 - 2003 ... 207 Ice-nucleating ability of soot particles in UT/LS J. Suzanne * ,D. Ferry F. CRMC2-CNRS, Campus de Luminy, Case 913, F-13288 Marseille cedex 9, France ...
The impact of volcanic eruptions on the marine carbon cycle is investigated for the example of th... more The impact of volcanic eruptions on the marine carbon cycle is investigated for the example of the Pinatubo eruption with model simulations of the distribution of the ash cloud and deposition on the ocean surface and the impact of the nutrient addition from ash leachates on the oceanic biological production and hence biological carbon pump. Natural variations of aerosols, especially due to large-magnitude volcanic eruptions, are recognized as a significant climate forcing, altering the Earth's radiation balance and thus tending to cause global temperature changes. While the impact of such events on climate and the terrestrial biosphere is relatively well documented, scientific knowledge of their effects on marine ecosystems and consequent feedbacks to the atmosphere is still very limited. In the deep sea, subaerial eruptive events of global significance are commonly recorded as widespread ash layers, which were often found to be associated with increased abundances of planktic organisms. This has led to the hypothesis that the influx of volcanic ash may provide an external nutrient source for primary production (in particular through iron fertilization) in ocean surface waters. Recent laboratory experiments have demonstrated that pristine volcanic ash indeed releases significant amounts of macronutrients and bioactive trace metals (including phosphate, iron and silica) adsorbed to the surface of the ash particles. The release of these components most likely has its largest impact in ocean regions where their availability is crucial for the growth of oceanic biomass, which are the high-nutrient but low-productivity (low-iron) areas in the Pacific and the Southern Ocean. These in turn are neighbored by most of those subaerially active volcanoes that are capable of ejecting huge amounts of aerosols into the high-velocity stratospheric wind fields. The dispersal and fallout of ash thus has a high potential to induce globally significant, transient net CO2 removal from the upper ocean and hence the atmosphere. Large-magnitude eruptions such as of Mount Pinatubo in 1991 were in fact followed by a slowing-down in the increase of atmospheric CO2 for several years, entailing a weakening of the global warming trend. For Mount Pinatubo it has been argued that the estimated CO2 uptake (1.6 x 1015 g C) could have been caused by rapid iron fertilization of the Southern Ocean with about 6.3 x 1015 g of ash. However, this would approximate the overall amount of the ash generated by the eruption, of which about 80% fell out over the South China Sea (~4.9 x 1015 g). This suggests additional avenues for the removal of CO2, among which the 1991 explosive eruption of Cerro Hudson could have played an important role as more than 2 km3 of the aerosols released by the volcano fell out directly over the Southern Ocean.
Egu General Assembly Conference Abstracts, May 1, 2010
Volcanic aerosols are an active component of the climate system and play multiple roles in physic... more Volcanic aerosols are an active component of the climate system and play multiple roles in physical and biogeochemical exchanges between the atmosphere, land, surface and ocean. To study the influence of volcanic aerosol on atmospheric dynamics and composition, dependent on the geographical latitude, interactive simulations of major volcanic eruptions are required. For our studies we use the middle atmosphere general circulation model MAECHAM5 including the global aerosol module HAM. HAM calculates the aerosol microphysics of sulfate and other species and their source and sink processes. The model setup has been validated for the Pinatubo eruption, showing good agreement with satellite data. Model studies have been performed for different major volcanic eruptions in the tropics and mid and high Northern latitudes (Pinatubo, Vesuvius, Katmai) with the strength and the eruption height of the Pinatubo eruption. All volcanic eruptions have been initialized in Northern Hemisphere summer and calculated for two years. The global distribution of the aerosol optical depth shows that the Pinatubo cloud is distributed over both hemispheres and has a global effect on climate. Volcanic aerosol of the Vesuvius eruption is mostly located in the Northern Hemisphere and has a more hemispheric effect but a certain fraction is also found in the Southern Hemisphere. Similar to the Pinatubo eruption the Vesuvius cloud is distributed fast to the north with the transition from summer to winter circulation. The volcanic aerosol of a Katmai eruption is only found in the Northern Hemisphere between 30°N und 90°N. The atmospheric life time of the volcanic aerosol varies with the geographic latitude of the volcano, Katmai has the shortest life time with 1.5 years and Pinatubo the longest one with 2.5 years. The strongest stratospheric temperature anomalies occur for the Pinatubo eruption in the tropics although chemical feedback mechanism not included in our simulation which might dampen the effect.
In recent years, several methods have been suggested for "geoengineering" the c... more In recent years, several methods have been suggested for "geoengineering" the climate to limit global temperature increase. One of these geoengineering techniques follows the natural example of volcanic eruptions, emitting large amounts of sulfur dioxide (SO2) into the stratosphere. Chemical and microphysical reactions cause the formation of sulfate aerosols, which reduces the incoming solar radiation. Recently, several studies on this
Super eruptions exert an extreme forcing on the Earth System. The emitted volcanic aerosol stays ... more Super eruptions exert an extreme forcing on the Earth System. The emitted volcanic aerosol stays several years in the stratosphere, causing strong radiative effects with consequences for atmospheric processes. The interactive simulation of formation, dispersal and temporal development of a very large volcanic cloud is a challenging task for every aerosol climate model. For our studies we use the middle