This product is being developed by The Cooperative Institute for Research in the Atmosphere (CIRA) in Fort Collins, Colorado, together with the NOAA/NESDIS/STAR RAMM Branch.
The Red-Blue-Green (RGB) Dust Product is being disseminated to the NOAA’s National Hurricane Center (NHC) via secure web pages using Keyhole Markup Language (KML) files, which can be displayed at NHC using Google Earth. This dissemination method was coordinated with NHC and fits within NOAA’s overarching network security. Furthermore, imagery and RGB products are being archived for the duration of the Proving Ground Demonstration period and can be supplied to NHC for post-season applications.
Original hi-res (3 km) images of 4096 x 4096 pixels are created every 15 minutes along with a text file with image coordinates for geolocation.
The purpose of the product is to provide NHC forecasters with an additional decision aid product. The product is an RGB composite based upon infrared channel data from the Meteosat Second Generation (MSG) satellite. It is designed to monitor the evolution of dust storms during both day and night. Dust plumes in the tropical Atlantic have been hypothesized to slow tropical storm development and directly affect sea surface temperatures (SSTs) where tropical cyclones form (Evan et al. 2008).
The RGB dust product demonstrates the kind of imagery that will be possible in the GOES-R era. The product is currently based on MSG data, simulating the future features the GOES-R Advanced Baseline Imager (ABI) sensor. ABI will be able to produce both a higher spatial resolution (2 km), higher temporal resolution (5 min), and higher spectral resolution than the current GOES satellites do.
The RGB Dust product is generated from MSG channels 7 (IR8.7), 9 (IR10.8), and 10 (IR12.0). The raw imagery is ingested from NESDIS operational servers and generated using MCIDAS and the following recipe developed by European Organization for the Exploitation of Meteorological Satellites (EUMETSAT).
| Beam | Channel | Range | Gamma |
|---|---|---|---|
| Red | IR12.0 – IR10.8 | -4 …. +2 K | 1 |
| Green | IR10.8 – IR8.7 | 0 …. +15 K | 2.5 |
| Blue | IR10.8 | +261 … +289 K | 1 |
The use of a gamma factor other than one means that the scaled difference is stretched using a power of 1/? [e.g., in this case d1/?, where d is scaled brightness temperature difference (i.e., 0 to 1 over a range of 0 to 15 K)].
The dust product is an RGB composite based upon infrared channel data from the MSG satellite. It was designed by EUMETSAT to monitor the evolution of dust storms during both day and night. The Dust RGB makes use of channel differences that are close to IR windows near 8.7 µmicro;m and 11 µmicro;m. The resulting product depicts dust in magenta and purple colors over land depending on the whether it is day or night, respectively. A dusty atmosphere can also be tracked the over water as magenta coloring. For more information on interpretation see (Kirkman et al., cited 2010). The product will allow for the monitoring of dust storms over the African Continent and tracking of that plume into the tropical Atlantic waters where easterly waves move and sometimes develop into tropical cyclones. The dust serves as a tracer for a dry mid-level airmass, and has radiative influences on the atmosphere and affects the microphysics of cloud development. Dust plumes in the tropical Atlantic have been hypothesized to slow tropical storm development (Dunion and Velden 2004) and directly affect sea surface temperatures (SSTs) where tropical cyclones form (Evan et al. 2008). An annotated example is provided below.
Figure 2: Dust product example. Dust is shown in magenta (day) or purple (night), water topped clouds show up as yellowish orange, ice topped clouds are shown in reddish orange, and thin cirrus is black.
Google Earth loops of GOES-E imagery over the CONUS are available at http://rammb.cira.colostate.edu/products/google_earth/
Dunion, J. P., and C. S. Velden (2004), The impact of the Saharan air layer on Atlantic tropical cyclone activity, Bull. Am. Meteorol. Soc., 85, 353-365.
Evan, A. T., R. Bennartz, V. Bennington, H. Corrada-Bravo, A. K. Heidinger, N. M. Mahowald, C. S. Velden, G. Myhre & J. P. Kossin (2008) Ocean temperature forcing by aerosols across the Atlantic tropical cyclone development region. Geochem. Geophys. Geosyst., 9, Q05V04, doi:10.1029/2007GC001790.
Kirkman, J., HP. Roesli, G. Bridge and M. König, cited 2010: Applications of Meteosat Second Generation (MSG), RGB Composites with Channels 01-11 and their interpretation. [Available on-line at http://oiswww.eumetsat.org/IPPS/html/bin/guides/msg_rgb_dust.ppt]
The RGB dust product provides an additional decision aid tool to NHC forecasters. This product helps tropical cyclone forecasters to track dust plumes in the tropical Atlantic. Dust storms have been hypothesized to slow tropical storm development and directly affect sea surface temperatures (SSTs). The current product is limited to the MSG sector.