Global trends in visibility: implications for dust sources
International audience There is a large uncertainty in the relative roles of human land use, climate change and carbon dioxide fertilization in changing desert dust source strength over the past 100 years, and the overall sign of human impacts on dust is not known. We used visibility data from meteo...
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ftinsu:oai:HAL:hal-00296267v1 2023-11-12T04:22:46+01:00 Global trends in visibility: implications for dust sources Mahowald, N. M. Ballantine, J. A. Feddema, J. Ramankutty, N. National Center for Atmospheric Research Boulder (NCAR) Institute for Computational Earth System Science Santa Barbara (ICESS) University of California Santa Barbara (UC Santa Barbara) University of California (UC)-University of California (UC) Department of Geography University of Kansas Kansas City Department of Geography Montréal McGill University = Université McGill Montréal, Canada 2007-06-26 https://hal.science/hal-00296267 https://hal.science/hal-00296267/document https://hal.science/hal-00296267/file/acp-7-3309-2007.pdf en eng HAL CCSD European Geosciences Union hal-00296267 https://hal.science/hal-00296267 https://hal.science/hal-00296267/document https://hal.science/hal-00296267/file/acp-7-3309-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 1680-7316 EISSN: 1680-7324 Atmospheric Chemistry and Physics https://hal.science/hal-00296267 Atmospheric Chemistry and Physics, 2007, 7 (12), pp.3309-3339 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2007 ftinsu 2023-10-25T16:29:29Z International audience There is a large uncertainty in the relative roles of human land use, climate change and carbon dioxide fertilization in changing desert dust source strength over the past 100 years, and the overall sign of human impacts on dust is not known. We used visibility data from meteorological stations in dusty regions to assess the anthropogenic impact on long term trends in desert dust emissions. We did this by looking at time series of visibility derived variables and their correlations with precipitation, drought, winds, land use and grazing. Visibility data are available at thousands of stations globally from 1900 to the present, but we focused on 357 stations with more than 30 years of data in regions where mineral aerosols play a dominant role in visibility observations. We evaluated the 1974 to 2003 time period because most of these stations have reliable records only during this time. We first evaluated the visibility data against AERONET aerosol optical depth data, and found that only in dusty regions are the two moderately correlated. Correlation coefficients between visibility-derived variables and AERONET optical depths indicate a moderate correlation (0.47), consistent with capturing about 20% of the variability in optical depths. Two visibility-derived variables appear to compare the best with AERONET observations: the fraction of observations with visibility less than 5 km (VIS5) and the surface extinction (EXT). Regional trends show that in many dusty places, VIS5 and EXT are statistically significantly correlated with the Palmer drought severity index (based on precipitation and temperature) or surface wind speeds, consistent with dust temporal variability being largely driven by meteorology. This is especially true for North African and Chinese dust sources, but less true in the Middle East, Australia or South America, where there are not consistent patterns in the correlations. Climate indices such as El Nino or the North Atlantic Oscillation are not correlated with ... Article in Journal/Newspaper North Atlantic North Atlantic oscillation Institut national des sciences de l'Univers: HAL-INSU |
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Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
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ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Mahowald, N. M. Ballantine, J. A. Feddema, J. Ramankutty, N. Global trends in visibility: implications for dust sources |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience There is a large uncertainty in the relative roles of human land use, climate change and carbon dioxide fertilization in changing desert dust source strength over the past 100 years, and the overall sign of human impacts on dust is not known. We used visibility data from meteorological stations in dusty regions to assess the anthropogenic impact on long term trends in desert dust emissions. We did this by looking at time series of visibility derived variables and their correlations with precipitation, drought, winds, land use and grazing. Visibility data are available at thousands of stations globally from 1900 to the present, but we focused on 357 stations with more than 30 years of data in regions where mineral aerosols play a dominant role in visibility observations. We evaluated the 1974 to 2003 time period because most of these stations have reliable records only during this time. We first evaluated the visibility data against AERONET aerosol optical depth data, and found that only in dusty regions are the two moderately correlated. Correlation coefficients between visibility-derived variables and AERONET optical depths indicate a moderate correlation (0.47), consistent with capturing about 20% of the variability in optical depths. Two visibility-derived variables appear to compare the best with AERONET observations: the fraction of observations with visibility less than 5 km (VIS5) and the surface extinction (EXT). Regional trends show that in many dusty places, VIS5 and EXT are statistically significantly correlated with the Palmer drought severity index (based on precipitation and temperature) or surface wind speeds, consistent with dust temporal variability being largely driven by meteorology. This is especially true for North African and Chinese dust sources, but less true in the Middle East, Australia or South America, where there are not consistent patterns in the correlations. Climate indices such as El Nino or the North Atlantic Oscillation are not correlated with ... |
author2 |
National Center for Atmospheric Research Boulder (NCAR) Institute for Computational Earth System Science Santa Barbara (ICESS) University of California Santa Barbara (UC Santa Barbara) University of California (UC)-University of California (UC) Department of Geography University of Kansas Kansas City Department of Geography Montréal McGill University = Université McGill Montréal, Canada |
format |
Article in Journal/Newspaper |
author |
Mahowald, N. M. Ballantine, J. A. Feddema, J. Ramankutty, N. |
author_facet |
Mahowald, N. M. Ballantine, J. A. Feddema, J. Ramankutty, N. |
author_sort |
Mahowald, N. M. |
title |
Global trends in visibility: implications for dust sources |
title_short |
Global trends in visibility: implications for dust sources |
title_full |
Global trends in visibility: implications for dust sources |
title_fullStr |
Global trends in visibility: implications for dust sources |
title_full_unstemmed |
Global trends in visibility: implications for dust sources |
title_sort |
global trends in visibility: implications for dust sources |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00296267 https://hal.science/hal-00296267/document https://hal.science/hal-00296267/file/acp-7-3309-2007.pdf |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
ISSN: 1680-7316 EISSN: 1680-7324 Atmospheric Chemistry and Physics https://hal.science/hal-00296267 Atmospheric Chemistry and Physics, 2007, 7 (12), pp.3309-3339 |
op_relation |
hal-00296267 https://hal.science/hal-00296267 https://hal.science/hal-00296267/document https://hal.science/hal-00296267/file/acp-7-3309-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782337702965805056 |