Title: The development of rainfall retrievals from radar at Darwin

Abstract

The U.S. Department of Energy Atmospheric Radiation Measurement program Tropical Western Pacific site hosted a C-band polarization (CPOL) radar in Darwin, Australia. It provides 2 decades of tropical rainfall characteristics useful for validating global circulation models. Rainfall retrievals from radar assume characteristics about the droplet size distribution (DSD) that vary significantly. To minimize the uncertainty associated with DSD variability, new radar rainfall techniques use dual polarization and specific attenuation estimates. This study challenges the applicability of several specific attenuation and dual-polarization-based rainfall estimators in tropical settings using a 4-year archive of Darwin disdrometer datasets in conjunction with CPOL observations. This assessment is based on three metrics: statistical uncertainty estimates, principal component analysis (PCA), and comparisons of various retrievals from CPOL data. The PCA shows that the variability in R can be consistently attributed to reflectivity, but dependence on dual-polarization quantities was wavelength dependent for 1 < R < 10 mm h^-1. These rates primarily originate from stratiform clouds and weak convection (median drop diameters less than 1.5 mm). The dual-polarization specific differential phase and differential reflectivity increase in usefulness for rainfall estimators in times with R > 10 mm h^-1. Rainfall estimates during these conditions primarily originate from deep convectivemore » clouds with median drop diameters greater than 1.5 mm. An uncertainty analysis and intercomparison with CPOL show that a Colorado State University blended technique for tropical oceans, with modified estimators developed from video disdrometer observations, is most appropriate for use in all cases, such as when 1 < R < 10 mm h^-1 (stratiform rain) and when R > 10 mm h^-1 (deeper convective rain).« less

Authors:

Jackson, Robert; Collis, Scott; Louf, Valentin ;

• Search DOE PAGES for author "Louf, Valentin"
• Search DOE PAGES for ORCID "0000-0001-8133-3031"

Protat, Alain ;

• Search DOE PAGES for author "Protat, Alain"
• Search DOE PAGES for ORCID "0000-0002-8933-874X"

Wang, Die ;

• Search DOE PAGES for author "Wang, Die"
• Search DOE PAGES for ORCID "0000-0002-4175-4306"

Giangrande, Scott ;

• Search DOE PAGES for author "Giangrande, Scott"
• Search DOE PAGES for ORCID "0000-0002-8119-8199"

Thompson, Elizabeth J. ;

• Search DOE PAGES for author "Thompson, Elizabeth J."
• Search DOE PAGES for ORCID "0000-0002-0131-4170"

Dolan, Brenda; Powell, Scott W.

• Search DOE PAGES for author "Powell, Scott W."
• Search DOE PAGES for ORCID "0000-0002-0306-8401"

Publication Date:

Mon Jan 04 00:00:00 EST 2021

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Atmospheric Radiation Measurement (ARM) Data Center; Argonne National Laboratory (ANL), Argonne, IL (United States). Laboratory Computing Resource Center (LCRC); Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); National Oceanic and Atmospheric Administration (NOAA)

Contributing Org.:

PNNL

OSTI Identifier:

1755464

Alternate Identifier(s):

OSTI ID: 1756293; OSTI ID: 1760169; OSTI ID: 1776800

Report Number(s):

BNL-220773-2021-JAAM
Journal ID: ISSN 1867-8548

Grant/Contract Number:  

SC0017977; AC02-06CH11357; SC0012704; SC0014063

Resource Type:

Published Article

Journal Name:

Atmospheric Measurement Techniques (Online)

Additional Journal Information:

Journal Name: Atmospheric Measurement Techniques (Online) Journal Volume: 14 Journal Issue: 1; Journal ID: ISSN 1867-8548

Publisher:

European Geosciences Union

Country of Publication:

Germany

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES