skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Wave like signatures in aerosol optical depth and associated radiative impacts over the central Himalayan region

Abstract

In this study, we present a case study on 16 October 2011 to show the first observational evidence of the influence of short period gravity waves in aerosol transport during daytime over the central Himalayan region. The Doppler lidar data has been utilized to address the daytime boundary layer evolution and related aerosol dynamics over the site. Mixing layer height is estimated by wavelet covariance transform method and found to be ~ 0.7 km, AGL. Aerosol optical depth observations during daytime revealed an asymmetry showing clear enhancement during afternoon hours as compared to forenoon. Interestingly, Fourier and wavelet analysis of vertical velocity and attenuated backscatter showed similar 50-90 min short period gravity wave signatures during afternoon hours. Moreover, our observations showed that gravity waves are dominant within the boundary layer implying that the daytime boundary layer dynamics is playing a vital role in transporting the aerosols from surface to the top of the boundary layer. Similar modulations are also evident in surface parameters like temperature, relative humidity and wind speed indicating these waves are associated with the dynamical aspects over Himalayan region. Finally, time evolution of range-23 height indicator snapshots during daytime showed strong upward velocities especially during afternoon hoursmore » implying that convective processes through short period gravity waves plays a significant role in transporting aerosols from the nearby valley region to boundary layer top over the site. These observations also establish the importance of wave induced daytime convective boundary layer dynamics in the lower Himalayan region.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1229987
Report Number(s):
PNNL-SA-104522
Journal ID: ISSN 1364-6826; 830403000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Atmospheric and Solar-Terrestrial Physics
Additional Journal Information:
Journal Volume: 133; Journal Issue: C; Journal ID: ISSN 1364-6826
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

Shukla, K. K., Phanikumar, D. V., Kumar, K.  Niranjan, Reddy, Kishore, Kotamarthi, V. R., Newsom, Rob K., and Ouarda, Taha B. M. J. Wave like signatures in aerosol optical depth and associated radiative impacts over the central Himalayan region. United States: N. p., 2015. Web. doi:10.1016/j.jastp.2015.08.001.
Shukla, K. K., Phanikumar, D. V., Kumar, K.  Niranjan, Reddy, Kishore, Kotamarthi, V. R., Newsom, Rob K., & Ouarda, Taha B. M. J. Wave like signatures in aerosol optical depth and associated radiative impacts over the central Himalayan region. United States. https://doi.org/10.1016/j.jastp.2015.08.001
Shukla, K. K., Phanikumar, D. V., Kumar, K.  Niranjan, Reddy, Kishore, Kotamarthi, V. R., Newsom, Rob K., and Ouarda, Taha B. M. J. 2015. "Wave like signatures in aerosol optical depth and associated radiative impacts over the central Himalayan region". United States. https://doi.org/10.1016/j.jastp.2015.08.001.
@article{osti_1229987,
title = {Wave like signatures in aerosol optical depth and associated radiative impacts over the central Himalayan region},
author = {Shukla, K. K. and Phanikumar, D. V. and Kumar, K.  Niranjan and Reddy, Kishore and Kotamarthi, V. R. and Newsom, Rob K. and Ouarda, Taha B. M. J.},
abstractNote = {In this study, we present a case study on 16 October 2011 to show the first observational evidence of the influence of short period gravity waves in aerosol transport during daytime over the central Himalayan region. The Doppler lidar data has been utilized to address the daytime boundary layer evolution and related aerosol dynamics over the site. Mixing layer height is estimated by wavelet covariance transform method and found to be ~ 0.7 km, AGL. Aerosol optical depth observations during daytime revealed an asymmetry showing clear enhancement during afternoon hours as compared to forenoon. Interestingly, Fourier and wavelet analysis of vertical velocity and attenuated backscatter showed similar 50-90 min short period gravity wave signatures during afternoon hours. Moreover, our observations showed that gravity waves are dominant within the boundary layer implying that the daytime boundary layer dynamics is playing a vital role in transporting the aerosols from surface to the top of the boundary layer. Similar modulations are also evident in surface parameters like temperature, relative humidity and wind speed indicating these waves are associated with the dynamical aspects over Himalayan region. Finally, time evolution of range-23 height indicator snapshots during daytime showed strong upward velocities especially during afternoon hours implying that convective processes through short period gravity waves plays a significant role in transporting aerosols from the nearby valley region to boundary layer top over the site. These observations also establish the importance of wave induced daytime convective boundary layer dynamics in the lower Himalayan region.},
doi = {10.1016/j.jastp.2015.08.001},
url = {https://www.osti.gov/biblio/1229987}, journal = {Journal of Atmospheric and Solar-Terrestrial Physics},
issn = {1364-6826},
number = C,
volume = 133,
place = {United States},
year = {Thu Oct 01 00:00:00 EDT 2015},
month = {Thu Oct 01 00:00:00 EDT 2015}
}