Graciosa Quicklook Homepage

Jayson Stemmler, Rob Wood

University of Washington



Data Descriptions and Use

Time Series Images

  • Radar Reflectivity: Vertical reflectivity of radar backscatter for the entire day (where available).
  • Lidar Backscatter: Vertical 180 degree lidar backscatter for the entire day
  • Cloud Mask: Cloud detection mask applied using a combination of lidar/radar data
  • Vertically Integrated Liquid Water Path
  • Cloud Condensation Nuclei (CCN)
  • Surface Precipitation

Vertical Soundings

  • Temperature and Dewpoint
  • Relative Humidity
  • Scattering Enhancement Factor and Lidar Backscatter

Satellite Imagery

source: NASA LANCE-MODIS Satellite Browse Imagery.
  • MODIS-bands1,4,3 (True-color): True-color imagery uses MODIS Bands 1, 4, and 3, respectively corresponding to the red, green, and blue range of the light spectrum, are assigned to the red, green, and blue channels of a digital image. These images are called true-color or natural color because this combination of wavelengths is similar to what the human eye would see.
  • Band 3,6,7 Combination: The 3-6-7 composite assigns Bands 3, 6, and 7 to the red, green, and blue components of a digital image. This combination is good for revealing snow and ice because they are very reflective in the visible part of the spectrum, and very absorbent in Bands 6 and 7, which are a part of the spectrum called the short-wave infrared, or SWIR
    • Snow and Ice: Since the only visible light used in these images (Band 3) is assigned to red, snow and ice appear bright red. The more ice, the stronger the absorption in the SWIR bands, and the more red the color. Thick ice and snow appear vivid red (or red-orange), while small ice crystals in high-level clouds will appear reddish-orange or peach.
    • Vegetation: Vegetation is absorbent in Band 3 and Band 7, but reflective in Band 6, and so will appear greenish in this band combination. Bare soil will appear bright cyan in the image since it much more reflective in Band 6 and Band 7 than Band 3.
    • Water: Liquid water on the ground will be very dark since it absorbs in the red and the SWIR, but small liquid water drops in clouds scatter light equally in both the visible and the SWIR, and will therefore appear white. Sediments in water appear dark red.

Mean Sea Level Pressure

The small maps show individual 6-hour model reanalysis mean sea-level pressure from the ECMWF global reanalysis model. The maps show msl pressure at 0, 6, 12, and 18 UTC. To view them all as a movie, follow the links below. The larger map shows the daily mean msl pressure from the same model. A loop of that can be found here: