TY - JOUR
T1 - Subseasonal Variability of Elevated Dust Concentrations Over South Florida
AU - Kramer, S. J.
AU - Kirtman, B. P.
AU - Zuidema, P.
AU - Ngan, F.
N1 - Funding Information:
Miami, Florida, dust mass concentration data set is available in netCDF and Excel format at https://doi.org/10.17604/q3vf‐8m31 . The National Centers for Environmental Prediction (NCEP) reanalysis data, a product provided by the NOAA/OAR/ESRL PSD Boulder, Colorado, USA, are available at https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html . The HYSPLIT model can be access from https://www.ready.noaa.gov/HYSPLIT.php , a NOAA Air Resource Laboratory product. B. P. K. acknowledges support from DOE DE‐SC0019433, NSF OCE1419569 and AGS1558837, and NOAA NA15OAR4320064. We also acknowledge thoughtful and valuable comments by the reviewers.
Funding Information:
Miami, Florida, dust mass concentration data set is available in netCDF and Excel format at https://doi.org/10.17604/q3vf-8m31. The National Centers for Environmental Prediction (NCEP) reanalysis data, a product provided by the NOAA/OAR/ESRL PSD Boulder, Colorado, USA, are available at https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html. The HYSPLIT model can be access from https://www.ready.noaa.gov/HYSPLIT.php, a NOAA Air Resource Laboratory product. B. P. K. acknowledges support from DOE DE-SC0019433, NSF OCE1419569 and AGS1558837, and NOAA NA15OAR4320064. We also acknowledge thoughtful and valuable comments by the reviewers.
Publisher Copyright:
© 2020. American Geophysical Union. All Rights Reserved.
PY - 2020/3/27
Y1 - 2020/3/27
N2 - Dust mass concentrations have been measured daily at Miami, Florida, in the summer months, and biweekly throughout the remaining months, since 1974. The 43-year record of dust mass concentrations indicate large daily, seasonal, and interannual variations, with most of the dust arriving within 5–8 episodes each summer. On average, dust arrives to Miami, Florida, 10 days after emission from North Africa, with measured concentrations depending on characteristics of the lower free-tropospheric winds due to the vast travel distance. Daily dust mass concentrations from July and August, the months that contribute the most to the annual mean, are used to characterize the synoptic conditions most favorable for dust transport. Two key regions are linked with the highest daily dust mass concentrations above Miami: (i) easterly winds, averaged over 850–500 mb, over the Tropical West Atlantic [15–25°N, 45–80°W], and (ii) southerly winds, similarly averaged, over the Florida Peninsula [20–30°N,75–80°W]. Winds within these two regions are enhanced when the North Atlantic subtropical high is displaced south and zonally elongated, relocating the western edge over Florida. A dust-transport-efficiency index, based on the maximum potential for dust to arrive above Miami with limited loss to deposition or mixing, identifies high-dust loading cases on the subseasonal scale. Monthly dust-transport-efficiency values agree well with the monthly dust trends over the 43-year time span. While seasonal dust loadings have been decreasing over Florida in the past decade, the transport efficiency has been increasing, possibly due to trends in the North Atlantic subtropical high.
AB - Dust mass concentrations have been measured daily at Miami, Florida, in the summer months, and biweekly throughout the remaining months, since 1974. The 43-year record of dust mass concentrations indicate large daily, seasonal, and interannual variations, with most of the dust arriving within 5–8 episodes each summer. On average, dust arrives to Miami, Florida, 10 days after emission from North Africa, with measured concentrations depending on characteristics of the lower free-tropospheric winds due to the vast travel distance. Daily dust mass concentrations from July and August, the months that contribute the most to the annual mean, are used to characterize the synoptic conditions most favorable for dust transport. Two key regions are linked with the highest daily dust mass concentrations above Miami: (i) easterly winds, averaged over 850–500 mb, over the Tropical West Atlantic [15–25°N, 45–80°W], and (ii) southerly winds, similarly averaged, over the Florida Peninsula [20–30°N,75–80°W]. Winds within these two regions are enhanced when the North Atlantic subtropical high is displaced south and zonally elongated, relocating the western edge over Florida. A dust-transport-efficiency index, based on the maximum potential for dust to arrive above Miami with limited loss to deposition or mixing, identifies high-dust loading cases on the subseasonal scale. Monthly dust-transport-efficiency values agree well with the monthly dust trends over the 43-year time span. While seasonal dust loadings have been decreasing over Florida in the past decade, the transport efficiency has been increasing, possibly due to trends in the North Atlantic subtropical high.
KW - North Atlantic subtropical high
KW - Saharan dust
KW - long range transport
KW - seasonal variability
KW - subseasonal variability
KW - tropical meteorology
UR - http://www.scopus.com/inward/record.url?scp=85082318979&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85082318979&partnerID=8YFLogxK
U2 - 10.1029/2019JD031874
DO - 10.1029/2019JD031874
M3 - Article
AN - SCOPUS:85082318979
VL - 125
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 6
M1 - e2019JD031874
ER -