GACP Datasets

Westphal Dataset

Date: Fri, 2 Apr 1999 12:32:16 -0800 (PST)
From: Douglas Westphal
Subject: Real-Time Aerosol Data and Analysis

A. NRL/MRY Aerosol Web Page

Our long-term goal at the Naval Research Laboratory in Monterey is to produce regional and global aerosol analyses and forecasts. At our web site, http://www.nrlmry.navy.mil/aerosol we have collected a number of real-time aerosol-related products and documentation on those products. Some we generate, others are mirrors of other sites or pointers to those sites.

The major ones are:

  • NAAPS (Navy Aerosol Analysis and Prediction System) aerosol analyses
  • Analysis of aerosol-related synoptic surface observations
  • NASA/GSFC TOMS aerosol index
  • NOAA/NESDIS aerosol optical depth
  • NRL-processed AVHRR, GMS, GOES, and METEOSAT imagery
  • NOGAPS (Navy Operational Global Analysis and Prediction System) weather/dynamic fields

A powerful tool is created by combining the TOMS aerosol index images with the NAAPS aerosol optical depths. An eight-day loop of this combination can be found at: http://www.nrlmry.navy.mil/aerosol/toms_globaer_dateline_loop.html

(The loop can be slow to load.) If you click through one image at a time (upper-right buttons) you will see that TOMS shows hints of broken filaments crossing the Pacific. NAAPS agrees with the location and timing of many of these broken filaments and also fills in the gaps. No quantitative validation has yet been carried out. The combination also shows that NAAPS has skill over the Sahara and Mid East, but incorrectly simulates dust storms over Australia.

After you become familiar with the products and documentation on the main page, you may find the quick-loading page to be more convenient: http://www.nrlmry.navy.mil/aerosol/index_shortcuts.html

Case studies of recent Chinese, Saharan, Arabian, Mediterranean etc. dust events can be found in: http://www.nrlmry.navy.mil/aerosol/Case_studies/case_studies.html

B. Recent Asian Dust Episode

One conclusion from my investigation of the big April 1998 Chinese dust storm was that I needed to monitor these events on a daily basis so that I could warn the instrumentalists and other observers of these events. Collecting the above data in one location makes this possible.

This spring, I have been following the NAAPS global aerosol analyses closely. There have been a number of Asian events, as well as Saharan events, with asian dust reaching N. America. Ken Sassen (U. Utah) has alerted us to dust in the mid- and upper-troposphere over Utah periodically during March. (Red-faced admission: We missed these at first because our minimum optical depth contour was 0.2. Now it is set at 0.05 and the events are detected.)

An good example has just occurred. Dust was lifted in the Gobi on the 15th and arrived at North America on the 21st. See: http://www.nrlmry.navy.mil/aerosol/Case_studies/19990322_pac/19990322_pac.html

At this page, I explain that while the simulations indicate dust is dominant, there may be sulfate and biomass smoke involved also. More analysis is required.

NAAPS will simulate smoke, but we have not found a global smoke or fire product to use to specify smoke sources. Hence, the lower-right panel in the NAAPS products is blank.

C. Future Model Development

NAAPS is still in a developmental stage, and will be for some time. However, I believe that showing preliminary NAAPS results is not as reckless as those who presented cold fusion. ;-)

NAAPS strengths are in:

  1. using operational dynamics, eg. 'REAL' weather
  2. running in near-real-time
  3. running globally
  4. dust modeling

Our current work involves:

  1. improving the dust source function
  2. finding a daily global smoke source product
  3. generating aerosol FORECASTS by driving NAAPS with the weather FORECASTS, as opposed to ANALYSES.
  4. improving the microphysics and chemistry.
  5. validating the sulfate simulations

I hope you find the site useful.

Douglas L. Westphal
Naval Research Laboratory
7 Grace Hopper Street, Stop 2
Monterey, CA 93943-5502
phone: (831) 656-4743
fax: (831) 656-4769
email:westphal@nrlmry.navy.mil
web: http://www.nrlmry.navy.mil/aerosol