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Archive for the ‘CrIS’ Category

Author: Emily Berndt

This week NASA SPoRT began producing and disseminating real-time Cross-track Infrared and Microwave Sounding Suite (CrIMSS) ozone products to the Ocean Prediction Center, Weather Prediction Center, and Satellite Analysis Branch. CrIMSS retrievals are a combination of retrievals from the Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) instruments aboard the NOAA/NASA Suomi NPP satellite which is our Nation’s next generation polar-orbiting operational environmental satellite system. Since CrIS is an infrared sounder its ability to detect atmospheric variables through cloudy regions is limited, therefore the retrievals are combined with ATMS retrievals to view atmospheric variables in partly cloudy regions. Despite the use of microwave retrievals, retrievals are still degraded or blocked by thick clouds, similar to AIRS. Recall AIRS infrared retrievals are also combined with microwave retrievals from the Advanced Microwave Sounding Unit (AMSU) to overcome this limitation of the infrared sounder.

Expanding the ozone products to included CrIMSS retrievals will provide National Center forecasters with additional retrievals to evaluate for identifying stratospheric air related to forecasting rapid cyclogenesis and high-wind events.

While the CrIMSS algortihm differs from AIRS, the creation of ozone products using CrIMSS is the first step to expanding SPoRT’s ozone products to the next generation instrumentation aboard the Suomi NPP satellite. There are slight variations in the retrievals, but decent agreement in ozone concentration is observed between AIRS and CrIMSS retrievals. Retrievals processed via The NOAA Unique CrIS/ATMS processing System (NUCAPS) are planned for release this summer. NUCAPS is a version of the AIRS Science Team Algorithm. Once SPoRT has access to the NUCAPS retrievals the CrIS ozone product will be updated. The advantage of the NUCAPS retrievals will be the the ability to directly compare the AIRS and CrIS/ATMS ozone retrievals across satellite platforms/instruments and provide forecasters with greater spatial and temporal coverage.

The four images below are an example of consecutive AIRS and CrIMSS ozone retrievals now available to forecasters in N-AWIPS format.

1400 UTC 14 May 2014 AIRS Total Column Ozone

1400 UTC 14 May 2014 AIRS Total Column Ozone

1500 UTC 14 May 2014 CrIMSS Total Column Ozone

1500 UTC 14 May 2014 CrIMSS Total Column Ozone

1600 UTC 14 May 2014 AIRS Total Column Ozone

1600 UTC 14 May 2014 AIRS Total Column Ozone

1700 UTC 14 May 2014 CrIMSS Total Column Ozone

1700 UTC 14 May 2014 CrIMSS Total Column Ozone

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Level 2 retrieved temperature and moisture profiles in clear and partly cloudy conditions can be obtained from the new Cross-track Infrared Microwave Sounding Suite (CrIMSS), which uses infrared measurements from the Cross-track Infrared Sounder (CrIS) and microwave measurements from the Advanced Technology Microwave Sounder (ATMS).  These observations are available from the Suomi-NPP as operational legacy observations to those coming on the JPSS.

SPoRT has begun processing the 42-level temperature and 22-level moisture CrIMSS Environmental Data Record (EDR) data and qualitatively comparing these soundings to other hyperspectral sounders (AIRS and IASI), in situ observations (RAOBs), and regional models (North American Mesoscale (NAM) and Rapid Refresh (RAP)).  All of these comparisons are available on SPoRT’s hyperspectral sounding comparison page (http://weather.msfc.nasa.gov/sport/hyperspectral_comparisons/).

As an example of these comparisons, the three images below were taken from that webpage for soundings at Vandenberg Air Force Base (VBG) in California all valid around 2100 UTC on 31 March 2013.  Note that the CrIMSS and AIRS soundings both match very closely to the RAP temperature sounding with near-perfect agreement of tropopause height in the AIRS sounding and similar tropopause placement in the CrIMSS sounding.  Both the AIRS and CrIMSS soundings highlight a low-level moist conditions and mid-level dry conditions.  Satellite soundings in this form can be used by forecasters to gain additional confidence in their model guidance or obtain additional information in regions where there are not other upper air observations (such as over Northern Mexico and the Gulf of Mexico).

Temperature and dew point soundings at VBG at 2100 UTC on 31 March 2013.

Temperature and dew point soundings at VBG at 2100 UTC on 31 March 2013.

Temperature and dew point soundings from CrIMSS at VBG at 2100 UTC on 31 March 2013.

Temperature and dew point soundings from CrIMSS at VBG at 2100 UTC on 31 March 2013.

Temperature and dew point soundings from AIRS at VBG at 2100 UTC on 31 March 2013.  Thicker line indicates highest quality data.

Temperature and dew point soundings from AIRS at VBG at 2100 UTC on 31 March 2013. Thicker line indicates highest quality data.

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The Northeast is bearing down for a blizzard as two storm systems are expected to merge off the East Coast early Saturday morning. Currently, one low pressure center is near Lake Erie and the other one is off the Virginia coast (see surface map below). Once the two systems phase off the East Coast, the new system is expected to rapidly deepen to 970 mb. Blizzard conditions will result as 1-2 feet of snow falls and winds gust to as high as 70 mph.

HPC 1500 UTC Surface Analysis Feb. 8, 2013

HPC 1500 UTC Surface Analysis Feb. 8, 2013

From a satellite perspective, how can some of the new GOES-R imagery and AIRS profiles help identify significant features associated with this unique synoptic set up? Below is an RGB Air Mass image from 0634 UTC this morning. The image gives a clear view of the coastal storm. Notice the green colors to the south of the main cloud shield, indicated by a blue arrow. The green colors represent warm, moist tropical air that is being drawn into the storm.  This air mass will provide abundant moisture to produce the robust snow fall amounts expected. A VIIRS/CRiS RGB Air Mass image from 0733 UTC this morning gives a broader view of the Eastern United States and shows the structure of both storms. The storm situated over the Great Lakes will usher cold air into the Northeast. There are also green colors to the north and northwest of the Great Lakes storm however they indicate cold, moist air.

RGB1

NASA SPoRT Aqua MODIS RGB Air Mass Image  0634 UTC Feb. 8, 2013.
Yellow arrow points to ozone rich stratospheric air and Blue arrow points to warm, moist tropical air.

NASA SPoRT VIIRS/CRiS RGB Air Mass Image     0733 UTC Feb. 8, 2013.
Yellow arrow points to ozone rich stratospheric air

Stratospheric intrusions are commonly associated with rapidly developing cyclones and may be responsible for transporting higher momentum air to the surface to produce damaging winds at the surface. If we piece together information from the RGB Air Mass imagery, AIRS total column ozone, and a 300 mb map, can we find an explanation to why this system will be associated with strong wind gusts?  The 1200 UTC 300 mb observations, pictured below, show a 125 kt jet streak north of Maine. The red/orange colors in the MODIS RGB Air Mass imagery indicate the presence of a jet streak and high potential vorticity air.  The AIRS total column ozone, pictured below, indicates higher values of ozone in the same vicinity. The presence of high potential vorticity air and larger amounts of ozone signify higher momentum stratospheric air intruding into the troposphere. Some of this stratospheric air is being drawn into the Great Lakes storm, shown by the yellow arrows on the VIIRS/CRiS RGB Air Mass image. Unfortunately  there was not an AIRS pass to the east of the storm system to further confirm ozone-rich stratospheric air. As the system continues to progress, more AIRS data and RGB Air Mass data will be investigated to watch how stratospheric air is drawn into the storm and how it relates to the production of surface wind gusts.

300 mb Heights (dm) and Isotachs (kts) 1200 UTC Feb. 8, 2013. Image from NCAR RAL Real Time Weather Data website

AIRS Total Column Ozone 0630-0636 UTC            Feb. 8, 2013

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The early morning overpasses of the NASA Aqua Satellite and NASA/NOAA Suomi-NPP Satellite both captured the progress of extratropical cyclone (nee Hurricane) Sandy as it moved across Pennsylvania.  SPoRT blends data from the Suomi-NPP Cross-track Infrared Sounder (CrIS) with data from the Visible Infrared Imager Radiometer Suite (VIIRS) to produce the Air Mass RGB product because of water vapor and ozone channels missing from VIIRS.  SPoRT also produces the same imagery from the Moderate-resolution Imaging Spectroradiometer (MODIS), which contains all of necessary channels for product development.  These data are made available to the NWS/NCEP in their NAWIPS decision support system and are available in KML format for display in Google Earth.

Below are two images taken less than 30 minutes apart from the two satellites.  On top is the CrIS/VIIRS Air Mass RGB image taken at 0728 UTC on October 30.  The bottom image is the MODIS Air Mass RGB image taken at 0751 UTC on October 30.  While the CrIS/VIIRS image is at slightly lower resolution due to effects from the larger CrIS footprint, the imagery is quite useful in identifying all of the atmospheric features.  Both images captured the location and structure of the storm system’s cloudy areas.  Also, both images captured the green-shaded moist air over the midwest and Great Lakes and the dry air that was being wrapped into the Northeastern side of the storm.

The blended CrIS/VIIRS RGB image is a great example of the type of exciting product that we can expect from the Joint Polar Satellite System (JPSS) in the future in support of operational weather forecasting.

Air Mass RGB Image from NASA/NOAA CrIS and VIIRS instruments depicting Extratropical Cyclone Sandy at 0728 UTC on 30 October 2012. Note that the features in this image are very consistent with the features in the MODIS RGB image below.

Air Mass RGB Image from NASA’s MODIS (Aqua) instrument depicting Extratropical Cyclone Sandy at 0751 UTC on 30 October 2012.

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As mentioned in earlier blog posts, SPoRT is currently producing a suite of satellite imagery products in support of forecasting for Hurricane Sandy.  These products include multispectral (also called RGB) imagery that blends specific channels that are sensitive to different atmospheric characteristics.  They are used to identify different cloud and air mass features within and surrounding the storm.  The products are available to NWS/NCEP in their NAWIPS decision support system and in KML format for viewing via Google Earth.  All of the data that SPoRT provides to the NWS are also freely available on the SPoRT website or through download via anonymous FTP, so non-NWS decision makers and the public can access the data to track the storm.

VIIRS images are available on the SPoRT website (http://weather.msfc.nasa.gov/sport/) by selecting VIIRS under the “Real-Time Data” tab.  MODIS images are available on the SPoRT website by selecting MODIS under the “Real-Time Data” tab.

KMZ files for Google Earth are available for download via SPoRT’s FTP server.  Click on the links next to each product description to view a list of VIIRS or MODIS imagery available for download into Google Earth.

  • True Color RGB:  Shows a representation of what the naked eye would view from space.  VIIRS   MODIS
  • Air Mass RGB:  Shows different cloud and air mass features, including moist tropical air and dry stratospheric air that enable forecasters to determine how the storm is interacting with its environment.   VIIRS & CrIS   MODIS
  • Day-Night-Band:  Allows for imagery to be generated using reflected moonlight or emitted surface light.  This is especially helpful because other visible satellite imagery is not available at night.  This product shows the location of city lights in clear skies and can be used to depict the extent of power outages due to large storm systems.   VIIRS
  • Dust RGB:  Shows the location of dust, which can be a contributing factor to hurricane development.   VIIRS  MODIS
  • False Color RGB:  Enhanced imagery that can differentiate snow from cold cloud tops.   VIIRS  MODIS
  • Nighttime Microphysics RGB:  Used to differentiate clouds from low-level fog.  VIIRS  MODIS

Training on how to interpret the different imagery can be found in training modules developed by SPoRT.  These modules can be viewed on the SPoRT website by selecting Training under the “Transitions” tab.

SPoRT True Color RGB Image in Google Earth depicting Hurricane Sandy off the Carolina Coast at 1749 UTC on 28 October 2012

*UPDATE*:  It appears that the latest version of Google Earth (6.2) is cropping some of these KML images.  To view the full images, it is recommended to use Google Earth 6.1 to view the VIIRS imagery.  This older version can be downloaded by visiting the Google Earth download page (http://www.google.com/earth/download/ge/agree.html) and clicking the “advanced setup” link located below the Terms of Service.

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