importance of low light sensing lunar reflection-based features: terrestrial/atmospheric...

Importance of Low Light SensingImportance of Low Light SensingLunar reflection-based features:Lunar reflection-based features:

Terrestrial/atmospheric emission-based features:Terrestrial/atmospheric emission-based features:

DMSP/OLS 8/30/2004 0504 UTCDMSP/OLS 8/30/2004 0504 UTC11.0 11.0 µµm IR Windowm IR Window

GeorgetteGeorgette Eastern Eastern PacificPacific

15 N15 N

20 N20 N

125 W125 W 120 W120 W

Upper-LevelUpper-LevelCirculationCirculation

Lower-LevelLower-LevelCirculation Circulation ~200km SE~200km SE

Improving Tropical Improving Tropical Cyclone Fixes at NightCyclone Fixes at Night

• Exposed low-level circulation occurs when storms enter a high vertical shear environment

• Decoupling of the upper and lower level cloud fields

• Displacements between upper and lower level centers can exceed 100 km in some cases

Avoiding the “Sunrise Surprise”

• The ‘Milky Seas’ of maritime folklore are thought to be caused by vast populations of luminous bacteria

50 km• The VIIRS/DNB will provide

superior spatial resolution to OLS, and calibration needed to fully quantify.

• This is a new frontier of science, enabled by low light imagery, with potential far reaching importance to the oceanic biota response to climate change.

• Recent findings demonstrate the capability of detecting them at night via low-light satellite imagery.

‘‘Milky Sea’ BioluminescenceMilky Sea’ Bioluminescence

Back upBack up

Low Cloud Detection Low Cloud Detection 20041215 (0.24 full moon)

20050104 (0.33 full moon)

20041220 (0.75 full moon)

20041225 (full moon)

20041230 (0.81 full moon)

Nocturnal Cloud Overlap DetectionNocturnal Cloud Overlap Detection

VIS/IR-based methods for detecting cloud overlap during the day will now be available at night via calibrated DNB observations. In the above example, the OLS reveals a low cloud deck (C) that is obscured by upper level cirrus (A). Other areas of un-obscured low clouds (D) are more readily observed via lunar reflection than by spectral emissivity differences (B).

Lightning DetectionLightning Detection

Dense flash zones correlate with NLDN cloud-to-ground strike data, help identify convective rainfall region within the broader cold cloud field particularly in regions without dense surface network coverage.

Nighttime: IR Only Nighttime: IR Only

Detecting Dust at NightDetecting Dust at NightDaytime: MODIS VIS + IR

3 March 2004, 1110 GMT

Nighttime: OLS VIS + IR Nighttime: OLS VIS + IR

3 March 2004, 2017 GMT

Dust is extremely difficult to detect at night. Lunar reflection of pixels scaled within a prescribed temperature range reveal a large dust front at night coming off the Sahara. Other examples of mesoscale plumes (including Haboobs) have also been documented from the OLS.

500 km

Texas

Detecting Snow Cover at NightDetecting Snow Cover at Night

Use of moonlight and NIR/IR (i.e., blending OLS with GOES space/time-matched data) to decouple clouds and snow cover at night at high spatial resolution. Simulates what VIIRS will be able to do via multi-spectral combinations including the DNB. The technique also applies to sea ice detection (for maritime transportation safety).

25 December, 2004

Yellow =No ChangeRed =Lights OutGreen =New Lights

Courtesy C. Elvidge, NOAA/NGDC

New Orleans

DMSP/OLS 8/28/2005 0220 UTCDMSP/OLS 8/28/2005 0220 UTCDMSP/OLS 8/30/2005 0154 UTCDMSP/OLS 8/30/2005 0154 UTC

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Terrestrial Light MonitoringTerrestrial Light Monitoring

The higher resolution (0.74 km) nighttime lights background from VIIRS/DNB will enable superior ‘residual light’ applications. These techniques are useful for monitoring disaster-related power outages and correlate with anthropogenic emissions of greenhouse gases.

Subtracting a background reference image from current nighttime imagery reveals any ‘new lights’ in the scene. Combining DNB observations with other co-located VIIRS channels, we will be able to couple heat signatures with new lights to delineate active fires vs. smoldering hotspots (information that is useful for smoke flux specification in transport/dispersion models).

10/26/2003 0424Z DMSP F15

Fires + City Lights

Fires Isolated

10/26/2003 1840Z Terra MODIS

Detecting Active Fires at NightDetecting Active Fires at Night

Quantifying the Lunar InputQuantifying the Lunar Input

The DoD has invested considerable resources into preparing for the potential quantitative applications of a calibrated DNB on VIIRS. Included in this work is the development of a lunar spectral irradiance database, which when convolved with the DNB response function, will provide the top-of-atmosphere lunar input for any date/time over the course of the NPOESS mission.