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NASA SPoRT has developed a real-time application of the NASA Land Information System (LIS) that runs over much of the central and eastern United States. The LIS produces several products, including a suite of soil moisture products that can be used to help assess drought and flooding potential. There are four LIS soil moisture products that are made available to WFO Raleigh forecasters in AWIPS-2 and which are available online for the Southeast and for North Carolina.

A fairly significant rain event occurred across central North Carolina on 15 and 16 October 2014 as a cold front and a wave of low pressure moved across the region. Two day precipitation totals across the WFO RAH CWA (Fig. 1) indicated between 0.75 and 1.25 inches of rain fell across the western Piedmont with much more significant amounts generally ranging between 1.5 and 3.0 inches across the eastern Piedmont and Coastal Plain of North Carolina. The heaviest rain occurred across Franklin, eastern Wake, northern Johnston, and western Nash Counties.

Fig. 1. Analyzed two day two day precipitation totals across the WFO RAH CWA on 15 and 16 October 2014.

Fig. 1. Analyzed two day two day precipitation totals across the WFO RAH CWA on 15 and 16 October 2014.

One of the SPoRT-LIS fields that forecasters have found quite useful during the assessment is the one-week change in total column relative soil moisture (RSM, 0-2 m). The RSM is the ratio of the current volumetric soil moisture between the wilting and saturation points for a given soil type, with values scaling between 0% (wilting) and 100% (saturation). The one-week change product valid at 12 UTC on 14 October, just prior to the rain event, is shown in Fig. 2 with the RAH CWA outlined in red. This product indicates that much of the southern and eastern portions of the RAH CWA have experienced a relative soil moisture decrease during the previous week, while locations near the Virginia border, especially across the northern Piedmont have had a relative soil moisture increase.

Fig. 2. The one-week change in total column relative soil moisture valid at 12 UTC on 14 October 2014 with the RAH CWA outlined in red.

Fig. 2. The one-week change in total column relative soil moisture valid at 12 UTC on 14 October 2014 with the RAH CWA outlined in red.

This rainfall produced significant rises on many rivers and creeks across the northeast Piedmont and the Coastal Plain of North Carolina. Figure 3 shows the gage height on the Swift Creek at Hilliardston which had an uncharacteristic rapid response and the gage height on the Neuse River at Smithfield which exceeded flood stage.

Fig. 3. Gage heights for the Swift Creek at Hilliardston (left) and the Neuse River at Smithfield (right).

Fig. 3. Gage heights for the Swift Creek at Hilliardston (left) and the Neuse River at Smithfield (right).

It was noted that the locations that experienced the most significant rises along with some flooding where in the river basins that had a notable overlap of the one-week increase in total column relative soil moisture prior to the event and the basins which experienced the most significant rainfall as shown in the composite image in Fig. 4.

Fig. 4. Composite chart of the one-week change in total column relative soil moisture valid at 12 UTC on 14 October and the analyzed two day two day precipitation totals on 15 and 16 October 2014 along with the locations of the gages for the Swift Creek at Hilliardston and the Neuse River at Smithfield.

Fig. 4. Composite chart of the one-week change in total column relative soil moisture valid at 12 UTC on 14 October and the analyzed two day two day precipitation totals on 15 and 16 October 2014 along with the locations of the gages for the Swift Creek at Hilliardston and the Neuse River at Smithfield.

SPoRT has been investigating options to obtain near-real time NUCAPS (NOAA Unique CrIS and ATMS Processing System) data to expand the ozone products to Suomi NPP retrievals.  The AIRS ozone products cover a Northwestern Hemisphere domain (Link to SPoRT AIRS products) and were specifically created for the National Centers (WPC and OPC) to aid interpretation of the Air Mass RGB for identifying and forecasting stratospheric intrusions that can lead to rapid cyclogenesis and hurricane-force wind events in the North Atlantic and North Pacific Oceans. The AIRS data are obtained from NASA Land Atmosphere Near-Real Time Capability for EOS (LANCE), rather than Direct Broadcast, so that the products can be created in hourly swaths that cover the OPC domain. Since the ozone products are created from polar-orbiting retrievals, forecasters are eager for better temporal and spatial resolution.  Use of retrievals from newer instruments such as Suomi-NPP CrIS/ATMS can provide additional overpasses to improve spatial and temporal resolution when paired with AIRS.

Suomi NPP data are available on the NOAA Comprehensive Large Array-Data Stewardship System (CLASS).  Typically data are obtained from CLASS by choosing options such as data type, domain, and time on the website and placing an order. Depending on the size of the order, it can take about an hour to 24 hours for your request to be processed and ready for download via ftp.  Manually placing an order is not an optimal approach for near-real time data processing and product development.

Recently SPoRT investigated the CLASS subscription service and has had success in obtaining NUCAPS data with a 2-3 hour latency. The CLASS subscription service is a valuable tool, comparable to NASA LANCE, for obtaining near-real time NUCAPS data. Others in the community who are interested in obtaining NUCAPS data with reduced latency and need a larger domain than what is available from Direct Broadcast should investigate the CLASS subscription service. Below is a outline of steps to set up a CLASS subscription for NUCAPS data.

First go to CLASS, create a user account and sign in. Click on “Subscriptions” in the left side menu. Choose your data product from the dropdown menu and click “Add New” to begin setting up the subscription details.  For NUCAPS choose S-NPP Data Exploitation Granule Data (NDE_L2)

Step1

Next, set up the search criteria for your subscription by choosing the domain either by making a box on the map or entering latitude and longitude values beside the map.  Click on the box next to “NUCAPS Environmental Data Records” and click on  “S-NPP”.  Click on “Delivery Options” to continue.

Step2

Last set up the delivery options.  Choose “yes” for a recurring schedule and set the start and end dates.  The start and end dates do not include the year, therefore you’ll need to modify the start and end date as the end of the year approaches.  Choose whether or not you want email notifications. I would initially choose “yes” so you can start to gauge how quickly your subscription is being processed from the time your data arrives in CLASS.  Note that you will get an email for every granule and sometimes the email notifications are delayed quite a bit after your data is ready.  The notifications are initially helpful as you first set-up your subscription. As a side note I did enjoy spamming myself with approximately 20-30 CLASS email notifications per hour when I first set up my subscription so I could see how it was working and could gauge the data latency.  Most important, choose how often you want to receive data in the dropdown list beside “Include delivery manifest”. I’ve chosen “Every 1 hour”, but depending on the product and your needs, you can choose any interval from 1-24 hours. Features such as the digital signature and checksum aren’t always necessary but you can decide if you need them by reading about them on the class help pages.  Now click “Save” to finish.

Step3

Once your subscription is set up, you can log in at any time to view, modify, or disable your subscription.  Just click on “Subscriptions” on the left side menu after you have logged in.

Once your data arrives in CLASS your order will be processed. Therefore the subscription service can provide automatic distribution of near-real time products as long as the data is arriving in CLASS near-real time. If the data is not pushed to CLASS near-real time by the product developer or NDE than the subscription service can’t be used for near-real time purposes (unless you don’t mind a 6-24 hour or longer latency).  Not all Suomi NPP products are pushed to CLASS in a real-real time capability. Thankfully NUCAPS is pushed to CLASS relatively quickly after it is processed and can be obtained via CLASS near-real time.  Your subscription will have a unique ID and your order will be available on the ftp site in a directory named with your username and subscription ID.  The data will also be available via a unique http site named with your username and subscription ID. Now your data is in one place and can be accessed via scripting and ftp without manually submitting an order on CLASS.

Latency of products getting to CLASS and figuring out how to order data without manually submitting an order on the website have been the largest deterrents for SPoRT using CLASS data for real-time product development.  Not all Suomi NPP data is immediately pushed to CLASS near-real time, however contacts at NESDIS have indicated that in the next 6-months or so, more Suomi NPP data will be pushed to CLASS in near-real time mode. Utilizing the CLASS subscription service opens up a new opportunity for SPoRT and the community to use NUCAPS data (and in the near future, other Suomi NPP data sets) from CLASS for product development.

More information on CLASS subscriptions can be found within the CLASS help pages.

One night after a widespread dense fog event, we have been monitoring more fog formation very closely.  Unlike the previous night, the visibility has not fallen quite so far, so fast at most of the airports across the Tennessee Valley; just a few sites in typically fog-prone valleys are reporting visibility of less than 1 mile.  However, coverage is the question, and the default 11-3.9 micron satellite imagery was not particularly helpful in diagnosing that.  There are hints of fog in the valleys of northeastern Alabama, but it’s tough to be sure how widespread the fog might be.

11-3.9 Micron GOES Imagery - 0800 UTC 27 October 2014

11-3.9 Micron GOES Imagery – 0800 UTC 27 October 2014

The Nighttime Microphysics RGB imagery was much, much more useful–and confirmed what the surface observations were telling us.  The 0802 UTC pass indicated that much of the fog is confined to the river valleys in and around the Huntsville CWFA, especially in the northeast Alabama valleys and the Elk River around the Tennessee-Alabama border (near where the mouse pointer is located).  Furthermore, the fainter gray-cyan colors surrounding the Tennessee River (bisecting the CWA) supported some of the less-dense fog reports coming from airports such as Muscle Shoals (KMSL) and Huntsville (KHSV).

Nighttime Microphysics RGB - 0802 UTC 27 October 2014

Nighttime Microphysics RGB – 0802 UTC 27 October 2014

This imagery helped confirm the surface observations, and helped with the decision to avoid a widespread dense fog advisory–at least temporarily.

Starting around 07Z last night, we noticed a station in the far northeast corner of Colorado reporting some reduction in visibility, with no other stations nearby reporting any reduction.  We couldn’t see any indication in the 11u-3.9u IR satellite imagery.  Once the VIIRS DNB imagery came in of the 09:04UTC imagery set, it was definitely evident in the Nighttime Microphysics channel, slightly in the Dust RGB channel, but not at all in the other DNB channels.  Good to know the sensor was reporting correctly!

20141026_0904_sport_viirs_frontrange_dnbrefrgb 20141026_0904_sport_viirs_frontrange_11um 20141026_0904_sport_viirs_frontrange_dust 20141026_0904_sport_viirs_frontrange_ntmicro

Seen above, top to bottom:  VIIRS DNB Reflectance RGB, IR Longwave, Dust RGB, Nighttime Microphysics imagery.  The latter definitely shows the small patch of fog clearly with the whiter (lower) clouds.

So, with the moon now passing into the waning crescent phase, the Day-Night Band imagery is less operationally useful, at least for the detection of fog and other lower level cloud types.  That is, at least until the moon is back into the waxing gibbous phase.  Nevertheless, when cirrus clouds aren’t present, the Nighttime Microphysics RGB has proven to be a very valuable tool for the detection of fog and other low-level clouds.  Just this morning a forecaster at the Huntsville, AL WFO was able to use the imagery not only for the detection of fog, but also to aid in the issuance of a special weather statement about the fog.  The image below valid at ~724 UTC (0224 am CDT) 17 Oct shows the fog (whitish-aqua colors) lying across the valley areas of NE Alabama and adjacent areas of southern Tennessee and NW Georgia.

MODIS Nighttime Microphysics RGB 724 UTC 17 October 2014

 

Around the time of this image, the visibility in the foggy locations had decreased to ~1/4 – 1/2 SM or less.  Notice the fog in the DeKalb Valley is fainter than the fog in areas to the north and west.  Not only is the DeKalb Valley more narrow, but the fog was likely more shallow.  This feature of the imagery can also help to guide forecasters in assessing the longevity of the fog once sunrise breaks.  Over time, forecasters can develop a sense of pattern recognition with the varying degrees of color shading and tailor forecasts to better match the time of dissipation.  In this case, the fog in the DeKalb Valley began to dissipate significantly by about 1430 UTC, while  the deeper and more expansive fog to the north and west lasted about an hour longer.

We are in the third and final month of assessing SPoRT’s real-time version of LIS running the Noah land surface model. The assessment is being conducted at the NWS forecast offices in Huntsville, Houston, and Raleigh to determine the utility of SPoRT-LIS for monitoring drought and areal flooding potential. The past 1-2 weeks featured substantial rainfall that occurred over a large portion of the central and eastern U.S.  Much of this precipitation was associated with a deep trough that progressed from the Southern Plains to the U.S. East Coast from 13-16 October.  Fairly widespread rainfall amounts exceeding 5 inches occurred over portions of eastern Oklahoma, south-western Missouri, western Arkansas, and in a swath extending from southeastern Arkansas to the southern Appalachians (Fig. 1).

Fig 1.  Depiction of 7-day rainfall estimates from the Stage IV radar+gauge product, ending 1200 UTC 16 October 2014.

Figure 1. Depiction of 7-day rainfall estimates from the Stage IV radar+gauge product, ending 1200 UTC 16 October 2014.

One of the SPoRT-LIS fields that forecasters have found quite useful during the assessment is the one-week change in total column relative soil moisture (RSM, 0-2 m).  The RSM is the ratio of the current volumetric soil moisture between the wilting and saturation points for a given soil type, with values scaling between 0% (wilting) and 100% (saturation).  In response to the recent substantial rainfall over the Deep South, the LIS total column RSM increased by 8-24+% over a large area (Fig. 2) approximately corresponding to the areas that received 4 or more inches of rainfall in the past week given by the orange and red shading in Figure 1. This beneficial rainfall led to the improvement of the U.S. Drought Monitor classification by 1-2 classes over portions of Kansas, Oklahoma, Texas, extending into Alabama, Tennessee, and northern Georgia (Fig. 3).  The most recent U.S. Drought Monitor product issued on 14 October (Fig. 4) shows that all drought classes have been removed over northern Alabama, Tennessee, and Kentucky.

Fig 2.  SPoRT-LIS one-week change in total column (0-2 m) relative soil moisture valid 1200 UTC 16 October 2014.

Figure 2. SPoRT-LIS one-week change in total column (0-2 m) relative soil moisture valid 1200 UTC 16 October 2014.

Fig 4.  One-week change in the U.S. Drought Monitor classifications, from 7 to 14 October 2014.

Figure 3. One-week change in the U.S. Drought Monitor classifications, from 7 to 14 October 2014.

Fig 3.  U.S. Drought Monitor classification valid 14 October 2014.

Figure 4. U.S. Drought Monitor classification valid 14 October 2014.

I wanted to follow up with this sooner, but I’ve been rather busy preparing for the NWA conference.  Yep, I tend to be one of those “last-minute” people.  Anyway, just last week I posted an example showcasing the advantage of the VIIRS Day-Night Band Radiance RGB in detecting fog through cirrus clouds.  The next day, SPoRT collaborator Doug Schneider (Morristown WFO), followed up with another great example that I wanted to share.  I’m just going to take an excerpt from an email he sent to the Morristown staff…

“I know I’ve been sending out quite a few emails lately about NASA SPoRT products, so please bear with me, but I thought this was a great example of how they can add value.

I’ve mentioned the MODIS/VIIRS Fog product before, but sometimes there are better products available for identifying fog, especially when thin cirrus are present. In the MODISVIIRS Fog product image that is attached, you can see that it is difficult to see the extent of fog. There’s clearly some in the Sequatchie Valley, but there is also some in the NE TN/SW VA area that can’t be easily seen.

The attached MODIS/VIIRS Nighttime Microphysics product also shows fog in the southern areas where it is clear (fog is light blue colors), but cirrus obscures NE sections.

The VIIRS Day/Night Band Radiance RGB product does the best job showing the extent of fog. Fog is clearly identified in the valleys of SW VA and NE TN, despite the presence of cirrus. The extent of fog is also more easily seen in the central and southern valley areas.

The attached menu image shows where you can find the Day/Night Band Radiance RGB product under the Satellite -> NASA SPoRT -> Polar Imager -> MODIS/VIIRS -> SR East menus.

Remember that these products are from a polar-orbiting satellite, and may only be available once a night, usually between 07z and 10z.”

I’ve included the images he referenced below, and circled the specific area of fog in NE Tennessee / SW Virginia that he was mentioning.

Suomi-NPP VIIRS Day-Night Band Radiance RGB, 0724 UTC 10 Oct 2014.  Circled area shows valley fog not detectable in subsequent GOES or VIIRS NT Microphysics images.

Suomi-NPP VIIRS Day-Night Band Radiance RGB, 0724 UTC 10 Oct 2014. Circled area shows valley fog not detectable in subsequent GOES or VIIRS NT Microphysics images.

Suomi-NPP VIIRS 11-3.9 um image, 0724 UTC 10 Oct 2014.  Notice that high cirrus clouds (blue colors) obscure the fog below.

Suomi-NPP VIIRS 11-3.9 um image, 0724 UTC 10 Oct 2014. Notice that high cirrus clouds (blue colors) obscure the fog below.

Suomi-NPP VIIRS Nighttime Microphysics RGB, 0724 UTC 10 Oct 2014.  Fog can be seen in other areas to the south/southwest, but not beneath the cold, cirrus clouds (under the yellow circle) since this RGB recipe contains multi-spectral IR components.

Suomi-NPP VIIRS Nighttime Microphysics RGB, 0724 UTC 10 Oct 2014. Fog can be seen in other areas to the south/southwest, but not beneath the cold, cirrus clouds (under the yellow circle) since this RGB recipe contains multi-spectral IR components.

This is exactly the kind of inter-office sharing SPoRT is looking for from our close partners.  We greatly thank Doug and the Morristown office for their collaborative efforts!

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