Displaying NUCAPS data from CLASS

November 12th, 2014

NUCAPS data have been flowing into AWIPS 2 for months; in the recent past, these data started flowing into the NOAA CLASS data archive as well (click here for a tutorial on accessing the data). How can the NOAA CLASS output be displayed? This post will compare McIDAS-V plots to the data displayed using AWIPS-1, below.

GOES Sounder Total Column Ozone DPI Values Plotted with NAM 500-mb heights and NAM Pressure on the 1.5 PVU surface (click to enlarge)

GOES Sounder Total Column Ozone DPI Values Plotted with NAM 500-mb heights and NAM Pressure on the 1.5 PVU surface (click to enlarge)

Suomi NPP overflew the central United States at about 0850 UTC on 12 November, and ozone concentrations from the NUCAPS soundings at three different levels (~500, 300 and ~200 mb) are shown below. Note that the color scaling is not quite the same in the three plots as the range for each pressure level is different. Maxima in Ozone at all levels occur in the same region — the Dakotas — as indicated by the GOES Sounder Total Column Ozone DPI, above. NUCAPS soundings also show data in cloudy regions because microwave data from ATMS is used in the NUCAPS processing. Note that values at the edge of the color shading have been extrapolated outwards; values in western Nevada and Indiana, for example, are not from direct NUCAPS observations. This plot of 500-mb temperatures (that includes the actual values) shows the horizontal extent of data and the amount of interpolation at the edge.

Contours of Ozone Mixing Ratio (parts per billion) from NUCAPS Soundings at ~0848 UTC on 12 November 2014 (click to enlarge)

Contours of Ozone Mixing Ratio (parts per billion) from NUCAPS Soundings at ~0848 UTC on 12 November 2014 (click to enlarge)

Mesoscale Convective System over the Southern Plains

October 6th, 2014
<strong>Suomi NPP VIIRS Day/Night Band (0.70 µm), Infrared Imagery (11.45 µm) and Day/Night Band imagery with lightning strikes at 0842 UTC on 6 October 2014</strong> (click to animate)

Suomi NPP VIIRS Day/Night Band (0.70 µm), Infrared Imagery (11.45 µm) and Day/Night Band imagery with lightning strikes at 0842 UTC on 6 October 2014 (click to animate)

The Suomi NPP VIIRS image toggle, above, from the pre-dawn hours (3:42 am local time) on 6 October 2014 shows a 0.7 µm Day/Night Band image and an 11.45 µm Infrared image, along with observations of postive and negative lightning strikes. With ample illumination by moonlight, the “visible image at night” Day/Night Band image highlighted areas of convective overshooting tops, but also included bright horizontal stripes that are associated with intense lightning activity; after scanning a particularly bright area of lightning in Arkansas, this image also showed a darker “post-saturation recovery” stripe downscan (to the southeast), which stretched from central Arkansas into Mississippi. This vigorous convective system dropped southeastward from Oklahoma towards the Gulf of Mexico, eventually becoming a Quasi-Linear Convective System (QLCS) which produced hail and wind damage (with one fatality) across parts of northeastern Texas and far northwestern Louisiana (SPC storm reports).

GOES Sounder DPI Lifted Index (click to animate)

GOES Sounder DPI Lifted Index (click to animate)

The southward-dropping Mesoscale Convective System followed a channel of unstable air as diagnosed by the GOES Sounder, above. Note that the Lifted Index values were smaller (less instability) along the path that the system had moved. Total Precipitable water was also enhanced in that corridor, suggesting a region where moisture return from the Gulf of Mexico was ongoing and concentrated.

GOES Infrared Imagery(10.7 µm) at 1600 UTC, and Pilot Reports of Turbulence (click to enlarge)

GOES Infrared Imagery (10.7 µm) at 1600 UTC, and Pilot Reports of Turbulence (click to enlarge)

Mesoscale Convective Systems can exhibit signatures that suggest the presence of turbulence in the atmosphere. In the GOES-13 IR image above, parallel filaments or “transverse bands” of cirrus  (extending approximately north-south) on the poleward side of the MCS suggest the presence of turbulence, and scattered pilot reports of Moderate Turbulence confirm that. Visible MODIS Imagery, below, also shows the transverse bands, as well as the outflow boundary arcing from Houston to the northwest and north.

Terra MODIS visible imagery (0.65 µm) at 1705 UTC  (click to enlarge)

Terra MODIS visible imagery (0.65 µm) at 1705 UTC (click to enlarge)

An animation of hourly GOES-13 Visible imagery, below, shows the motion of the western portion of the outflow boundary as the decaying QLCS moved into the Gulf of Mexico.

GOES-13 Visible (0.65µm) imagery (click to animate)

GOES-13 Visible (0.65µm) imagery (click to animate)

GOES-13 6.5 µm water vapor channel imagery, below, displayed a signature of subsidence immediately upstream of the dissipating MCS, in the form of an arc of warmer/drier (yellow to orange color enhancement) brightness temperatures that extended from the Texas coast into central Arkansas. One rapidly-developing convective cell which formed along the advancing outflow boundary was responsible for severe turbulence in eastern Texas; the subtle signal of the westward-propagating outflow boundary could also be followed on the water vapor imagery.

<strong>GOES-13 6.5 µm water vapor channel images, with pilot reports of turbulence</strong> (click to play animation)

GOES-13 6.5 µm water vapor channel images, with pilot reports of turbulence (click to play animation)

Strong early-season storm in the North Pacific

September 23rd, 2014
GOES-15 6.5 µm IR channel images (click to play animation)

GOES-15 6.5 µm IR channel images (click to play animation)

The GOES-15 6.5 µm water vapor channel imagery above showed the development and evolution of a strong mid-latitude cyclone in the eastern North Pacific Basin during the 21-23 September 2014 time period; of particular interest was the development of strong subsidence behind the storm (depicted by brighter shades of yellow), and also a second jet starting to approach the storm from the west (as evidenced by increasing cold cloud tops in the base of the trough at the end of the animation). A closer view of the storm using AWIPS II imagery is available here. The strong storm had access to abundant sub-tropical moisture, as depicted in the MIMIC Total Precipitable Water animation below.

MIMIC Total Precipitable Water (click to enlarge)

MIMIC Total Precipitable Water (click to enlarge)

The ASCAT Scatterometer that flies on METOP gives routine observations of surface winds over the ocean. A large area of storm-force winds (in red) was depicted in the image below (from 0630 UTC on 23 September), overlain on the GOES-15 Water Vapor imagery.

 GOES-15 6.5 µm water vapor channel image and ASCAT winds, 0630 UTC on 23 September (click to enlarge)

GOES-15 6.5 µm water vapor channel image and ASCAT winds, 0630 UTC on 23 September (click to enlarge)

A comparison of 4-km resolution GOES-15 6.5 µm and 1-km resolution Aqua MODIS 6.7 µm water vapor channel images at 11:30 UTC, below, demonstrated the benefit of higher spatial resolution for providing a more accurate display of the water vapor gradients and various small-scale features (such as transverse banding associated with cold clouds to the north of the storm), along with the polar-orbiter image elimination of geostationary parallax error for more more precise feature location.

GOES-15 6.5 µm and Aqua MODIS 6.7 µm water vapor channel images

GOES-15 6.5 µm and Aqua MODIS 6.7 µm water vapor channel images

The GOES sounder Total Column Ozone product, below, showed an increase in ozone values (350-380 Dobson Units, darker green to lighter green color enhancement) as the tropopause was lowered in the vicinity of the deepening mid-latitude cyclone.

GOES sounder Total Column Ozone product (click to play animation)

GOES sounder Total Column Ozone product (click to play animation)

A Suomi NPP VIIRS true-color image from the SSEC RealEarth web map server, below, provided a good view of the lower-level clouds associated with the storm.

Suomi NPP VIIRS true-color image

Suomi NPP VIIRS true-color image

For a more detailed analysis of this event from the Ocean Prediction Center perspective, see the Satellite Liaison Blog.

Record rainfall and flooding in Arizona

September 8th, 2014
GOES-15 10.7 µm IR channel images (click to play animation)

GOES-15 10.7 µm IR channel images (click to play animation)

McIDAS images of 4-km resolution GOES-15 10.7 µm IR channel data (above; click image to play animation; also available as an MP4 movie file) showed the merger of two large mesoscale convective systems (MCS) which produced an all-time record maximum calendar day precipitation amount of 3.29 inches at Phoenix Sky Harbor Airport (PHX) on 08 September 2014. Some locations in the Phoenix area received in excess of 5 inches of rainfall (NWS Phoenix event summary).

An AWIPS-II image of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel data (below) showed the MCS pair at 09:07 UTC or 3:07 AM local time —  this was prior to the merger, and the southeastern storm exhibited a minimum cloud-top IR brightness temperature of -84º C (purple color enhancement), which was much colder than the -71º C seen with the northwestern storm. At the onset of the heavy thunderstorms at PHX, southerly to southeasterly winds  — likely outflow from the southeastern MCS — gusted as high as 31 knots (36 mph) and visibility was reduced to 0.8 mile (surface reports: text | graph).

Suomi NPP VIIRS 11.45 µm IR channel image

Suomi NPP VIIRS 11.45 µm IR channel image

As the circulation of former-Hurricane Norbert continued to spin over the Pacific Ocean west of Baja California, deep tropical moisture kept working its way farther inland — GOES sounder Total Precipitable Water (TPW) values in excess of 50-60 mm (2.0 to 2.4 inches) were eventually seen across the southwestern half of Arizona (below; click image to play animation).

GOES sounder Total Precipitable Water derived product images (click to play animation)

GOES sounder Total Precipitable Water derived product images (click to play animation)

The Blended Total Precipitable Water product (below; click image to play animation) also showed values of 50-60 mm working their way into southwestern Arizona during the 06-08 September period.

Blended Total Precipitable Water product (click to play animation)

Blended Total Precipitable Water product (click to play animation)

The Percent of Normal TPW product (below; click image to play animation) indicated that these TPW values were in excess of 200% of normal (yellow color enhancement) over large portions of the Desert Southwest. On the morning of 08 September, the TPW value of 2.03 inches derived from rawinsonde data at Tucson, Arizona set a record high for the month of September at that location.

Percent of Normal TPW product (click to play animation)

Percent of Normal TPW product (click to play animation)