Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Deriving cloud droplet number concentration from surface-based remote sensors with an emphasis on lidar measurements

Journal Article · · Atmospheric Measurement Techniques (Online)

Abstract. Given the importance of constraining cloud droplet number concentrations (Nd) in low-level clouds, we explore two methods for retrieving Nd from surface-based remote sensing that emphasize the information content in lidar measurements. Because Nd is the zeroth moment of the droplet size distribution (DSD), and all remote sensing approaches respond to DSD moments that are at least 2 orders of magnitude greater than the zeroth moment, deriving Nd from remote sensing measurements has significant uncertainty. At minimum, such algorithms require the extrapolation of information from two other measurements that respond to different moments of the DSD. Lidar, for instance, is sensitive to the second moment (cross-sectional area) of the DSD, while other measures from microwave sensors respond to higher-order moments. We develop methods using a simple lidar forward model that demonstrates that the depth to the maximum in lidar-attenuated backscatter (Rmax⁡) is strongly sensitive to Nd when some measure of the liquid water content vertical profile is given or assumed. Knowledge of Rmax⁡ to within 5 m can constrain Nd to within several tens of percent. However, operational lidar networks provide vertical resolutions of > 15 m, making a direct calculation of Nd from Rmax⁡ very uncertain. Therefore, we develop a Bayesian optimal estimation algorithm that brings additional information to the inversion such as lidar-derived extinction and radar reflectivity near the cloud top. This statistical approach provides reasonable characterizations of Nd and effective radius (re) to within approximately a factor of 2 and 30 %, respectively. By comparing surface-derived cloud properties with MODIS satellite and aircraft data collected during the MARCUS and CAPRICORN II campaigns, we demonstrate the utility of the methodology.

Sponsoring Organization:
USDOE
OSTI ID:
2375546
Alternate ID(s):
OSTI ID: 2382672
Journal Information:
Atmospheric Measurement Techniques (Online), Journal Name: Atmospheric Measurement Techniques (Online) Journal Issue: 12 Vol. 17; ISSN 1867-8548
Publisher:
Copernicus GmbHCopyright Statement
Country of Publication:
Germany
Language:
English

References (40)

A two-moment cloud microphysics parameterization for mixed-phase clouds. Part 1: Model description journal October 2005
Pollution and the planetary albedo journal December 1974
Retrieval of stratus cloud microphysical parameters using millimeter-wave radar and visible optical depth in preparation for CloudSat: 1. Algorithm formulation journal November 2001
Remote Sensing of Droplet Number Concentration in Warm Clouds: A Review of the Current State of Knowledge and Perspectives journal June 2018
Cloud‐Nucleating Particles Over the Southern Ocean in a Changing Climate journal March 2021
Southern Ocean Cloud Properties Derived From CAPRICORN and MARCUS Data journal February 2021
Influences of Recent Particle Formation on Southern Ocean Aerosol Variability and Low Cloud Properties journal April 2021
On cloud radar and microwave radiometer measurements of stratus cloud liquid water profiles journal September 1998
Surface-based remote sensing of the observed and the Adiabatic liquid water content of stratocumulus clouds journal January 1990
The MODIS cloud products: algorithms and examples from terra journal February 2003
Inverse Methods for Atmospheric Sounding: Theory and Practice book July 2000
Full-Time, Eye-Safe Cloud and Aerosol Lidar Observation at Atmospheric Radiation Measurement Program Sites: Instruments and Data Processing journal April 2002
A Technique for Autocalibration of Cloud Lidar journal May 2004
Lidar Observation of a Mixed-Phase Altostratus Cloud journal April 1977
Backscatter-to-Extinction Ratios in the Top Layers of Tropical Mesoscale Convective Systems and in Isolated Cirrus from LITE Observations journal September 1999
Radiation Profiles in Extended Water Clouds. I: Theory journal November 1978
Determination of the Optical Thickness and Effective Particle Radius of Clouds from Reflected Solar Radiation Measurements. Part I: Theory journal August 1990
Diurnal Cloud and Thermodynamic Variations in the Stratocumulus Transition Regime: A Case Study Using In Situ and Remote Sensors journal July 1998
Cloud Droplet Size Distributions in Low-Level Stratiform Clouds journal January 2000
CALIPSO/CALIOP Cloud Phase Discrimination Algorithm journal November 2009
The Occurrence of Particle Size Distribution Bimodality in Midlatitude Cirrus as Inferred from Ground-Based Remote Sensing Data journal June 2011
Cloud Ice Properties: In Situ Measurement Challenges journal January 2017
Optimal Estimation Retrievals and Their Uncertainties: What Every Atmospheric Scientist Should Know journal September 2020
Observations of clouds, aerosols, precipitation, and surface radiation over the Southern Ocean: An overview of CAPRICORN, MARCUS, MICRE and SOCRATES journal November 2020
Objective Assessment of the Information Content of Visible and Infrared Radiance Measurements for Cloud Microphysical Property Retrievals over the Global Oceans. Part I: Liquid Clouds journal January 2006
Objective Assessment of the Information Content of Visible and Infrared Radiance Measurements for Cloud Microphysical Property Retrievals over the Global Oceans. Part II: Ice Clouds journal January 2006
MCMC-Based Assessment of the Error Characteristics of a Surface-Based Combined Radar–Passive Microwave Cloud Property Retrieval journal August 2014
A Study of Aerosol Impacts on Clouds and Precipitation Development in a Large Winter Cyclone journal October 2014
Aircraft Observations of Cumulus Microphysics Ranging from the Tropics to Midlatitudes: Implications for a “New” Secondary Ice Process journal September 2017
Advanced Two-Moment Bulk Microphysics for Global Models. Part I: Off-Line Tests and Comparison with Other Schemes journal February 2015
An Improved Liquid Water Absorption Model at Microwave Frequencies for Supercooled Liquid Water Clouds journal January 2016
The 2D-S (Stereo) Probe: Design and Preliminary Tests of a New Airborne, High-Speed, High-Resolution Particle Imaging Probe journal November 2006
Atmospheric Radiation Measurement (ARM) User Facility 2020 Decadal Vision report May 2021
MOD06_L2 MODIS/Terra Clouds 5-Min L2 Swath 1km and 5km null January 2015
A new method for retrieval of the extinction coefficient of water clouds by using the tail of the CALIOP signal journal January 2011
Southern Ocean latitudinal gradients of cloud condensation nuclei journal January 2021
Measurement report: Understanding the seasonal cycle of Southern Ocean aerosols journal March 2023
Global statistics of liquid water content and effective number concentration of water clouds over ocean derived from combined CALIPSO and MODIS measurements journal January 2007
Calibration of the 2007–2017 record of Atmospheric Radiation Measurements cloud radar observations using CloudSat journal January 2019
Determining cloud thermodynamic phase from the polarized Micro Pulse Lidar journal January 2020

Similar Records

Cloud Mask from Micropulse Lidar
Dataset · Mon Jul 15 00:00:00 EDT 2019 · OSTI ID:1508389
Micropulse Lidar Cloud Mask (MPLCMASK) Value-Added Product for the Fast-Switching Polarized Micropulse Lidar Technical Report
Technical Report · Wed Jul 01 00:00:00 EDT 2020 · OSTI ID:1019283

Related Subjects