Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito

Using our large data base from the Argentine site at El Leoncito that covers the years from August 1997 to May 2001, and four individual campaigns in 1986, 1987, and 1992, we search for trends in temperatures corresponding to heights of 87 and 95 km. Also the variations in OH and O2 airglow band int...

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Guardado en:
Detalles Bibliográficos
Publicado: 2002
Materias:
Airglow
Climate change
ENSO
Mesopause region
Southern
Temperature
Trends
Band structure
Data recording
Database systems
Geophysics
Oxygen
Temperature measurement
Time series analysis
Mesopause
Trend analysis
Atmospheric chemistry
airglow
long-term change
mesopause
temperature
Argentina
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14747065_v27_n6-8_p563_Reisin
http://hdl.handle.net/20.500.12110/paper_14747065_v27_n6-8_p563_Reisin
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_14747065_v27_n6-8_p563_Reisin
record_format dspace
spelling paper:paper_14747065_v27_n6-8_p563_Reisin2023-06-08T16:17:36Z Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito Airglow Climate change ENSO Mesopause region Southern Temperature Trends Band structure Data recording Database systems Geophysics Oxygen Temperature measurement Time series analysis Mesopause Trend analysis Atmospheric chemistry airglow long-term change mesopause temperature Argentina Using our large data base from the Argentine site at El Leoncito that covers the years from August 1997 to May 2001, and four individual campaigns in 1986, 1987, and 1992, we search for trends in temperatures corresponding to heights of 87 and 95 km. Also the variations in OH and O2 airglow band intensities for these two altitudes supply complimentary information interesting in terms of trends. The seasonal variation is well documented with good reproducibility, since the end of a perturbation possibly due to the 1997 ENSO event, so that the time series of nocturnal mean values can be reliably freed from the seasonal effect. Some difficulties arise from the geophysical variations (mostly from planetary waves) still present in the data averages over 28 nights of observation. In spite of this, temperature trends of a fraction of 1 K/year should be detectable, using only the data from 1998 to 2001. However, only at 95 km, there is a significant positive temperature trend over the last 4 year. When the earlier campaigns are included, this 15 year data span shows a negative temperature trend of about - 1 K/year and a positive (OH) intensity trend of about +1%/year, at 87 km. At 95 km, there is a similar (O2) intensity trend, but a temperature trend compatible with zero. These results are similar to previous findings for Northern Hemisphere midlatitude sites, by other investigators. As a by-product of the trend analysis, we also estimate values for the 1997 ENSO temperature anomaly of about -3.5 K at 87 km, and -6 K at 95 km. © 2002 Elsevier Science Ltd. All rights reserved. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14747065_v27_n6-8_p563_Reisin http://hdl.handle.net/20.500.12110/paper_14747065_v27_n6-8_p563_Reisin
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Airglow
Climate change
ENSO
Mesopause region
Southern
Temperature
Trends
Band structure
Data recording
Database systems
Geophysics
Oxygen
Temperature measurement
Time series analysis
Mesopause
Trend analysis
Atmospheric chemistry
airglow
long-term change
mesopause
temperature
Argentina
spellingShingle Airglow
Climate change
ENSO
Mesopause region
Southern
Temperature
Trends
Band structure
Data recording
Database systems
Geophysics
Oxygen
Temperature measurement
Time series analysis
Mesopause
Trend analysis
Atmospheric chemistry
airglow
long-term change
mesopause
temperature
Argentina
Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito
topic_facet Airglow
Climate change
ENSO
Mesopause region
Southern
Temperature
Trends
Band structure
Data recording
Database systems
Geophysics
Oxygen
Temperature measurement
Time series analysis
Mesopause
Trend analysis
Atmospheric chemistry
airglow
long-term change
mesopause
temperature
Argentina
description Using our large data base from the Argentine site at El Leoncito that covers the years from August 1997 to May 2001, and four individual campaigns in 1986, 1987, and 1992, we search for trends in temperatures corresponding to heights of 87 and 95 km. Also the variations in OH and O2 airglow band intensities for these two altitudes supply complimentary information interesting in terms of trends. The seasonal variation is well documented with good reproducibility, since the end of a perturbation possibly due to the 1997 ENSO event, so that the time series of nocturnal mean values can be reliably freed from the seasonal effect. Some difficulties arise from the geophysical variations (mostly from planetary waves) still present in the data averages over 28 nights of observation. In spite of this, temperature trends of a fraction of 1 K/year should be detectable, using only the data from 1998 to 2001. However, only at 95 km, there is a significant positive temperature trend over the last 4 year. When the earlier campaigns are included, this 15 year data span shows a negative temperature trend of about - 1 K/year and a positive (OH) intensity trend of about +1%/year, at 87 km. At 95 km, there is a similar (O2) intensity trend, but a temperature trend compatible with zero. These results are similar to previous findings for Northern Hemisphere midlatitude sites, by other investigators. As a by-product of the trend analysis, we also estimate values for the 1997 ENSO temperature anomaly of about -3.5 K at 87 km, and -6 K at 95 km. © 2002 Elsevier Science Ltd. All rights reserved.
title Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito
title_short Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito
title_full Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito
title_fullStr Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito
title_full_unstemmed Searching for trends in mesopause region airglow intensities and temperatures at El Leoncito
title_sort searching for trends in mesopause region airglow intensities and temperatures at el leoncito
publishDate 2002
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14747065_v27_n6-8_p563_Reisin
http://hdl.handle.net/20.500.12110/paper_14747065_v27_n6-8_p563_Reisin
_version_ 1768544611895083008

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