National Aeronautics and Space Administration

National Climate Assessment

NASA National Climate Assessment (NCA) Activities

NASA Centers Call for Proposals

National Climate Assessment - 2011 NASA Centers Call For Proposals

Lead PI and Center: William Koshak, Marshall Space Flight Center
Title:  Assessing Global Change Impact on the US Using National Lightning Data
Proposal type: Assessment Capabilities & Products
Lab website: http://lightning.nsstc.nasa.gov/index.html
News article: http://earthdata.nasa.gov/featured-stories/featured-research/cosmic-charges
Additional information: The MSFC Lightning Nitrogen Oxides Model (LNOM) Data Archive: http://lightning.nsstc.nasa.gov/data/index.html#LNOM_DATA

FINAL PROJECT SUMMARY

The National Lightning Detection NetworkTM (NLDN) has expanded across the continental United States (CONUS) and has experienced several technological upgrades over many years; because of upgrades in 2002-2003, it became a particularly useful tool for assessing the relationship between cloud-to-ground (CG) lightning characteristics and climate variability. This NCA work effort utilized the NLDN, and NOAA storm data reports, to provide a more comprehensive assessment of the co-evolution of temperature, lightning, & adverse lightning-caused impacts for the decade 2003-2012. It was found that while the average dry-bulb temperature over CONUS trended upward in the decade, both average wet-bulb temperature and CG activity trended downward. This supported the notion that CG lightning requires both heat & moisture (not just heat). Indeed, the hot/dry drought of 2012 revealed a minimum in CG activity; i.e. the lack of moisture resulted in below-average thunderstorm development. Across the decadal period, CG activity dropped by 12.8%, and CG-caused deaths, injuries, and wildfire all dropped. CG-caused property damage (a more complicated factor tied to economics, population and the types of buildings struck by lightning) increased. Other CG lightning characteristics, such as CG peak return stroke current and multiplicity (# of strokes in a flash) had relatively small changes. However, the fraction of CGs depositing positive charge to Earth (the so called +CG fraction, a marker for severe weather) trended upward and therefore will be monitored closely in the future. Overall, this effort found a sensitivity of +18% change in CG count if given a +1oC change in average CONUS wet bulb temperature, which is close to the recent (single year) estimate of 12% per oC  found in Romps et al. (2014). Also, by combining CG lightning data with national radar data, this effort found that a dry lightning indicator (DLI) was good at predicting lightning-caused wildfires; it performed better than CG or radar data alone.

In addition to applying NLDN data, this effort also examined total (CG + cloud flash) lightning data from the Lightning Imaging Sensor (LIS) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite. The LIS provided coverage up to 38oN latitude (i.e., across the southern tier of states where most of the lightning occurs) and the same decadal period (2002-2013) was analyzed. It was found that LIS total lightning was remarkably constant (increased by only 0.38%), implying that total lightning is evidently less sensitive to changes in wet bulb temperature. However, a fascinating result is that LIS-detected flash optical energies trended downward over the lifetime of LIS, a result that requires follow-on investigation. If this result is not linked to sensor degradation, then it could imply a downward trend in flash energy and hence lightning nitrogen oxides (LNOx) production, an important control on the greenhouse gas ozone.

Finally, this effort has helped initiate discussion between the NASA/MSFC and the Hamilton County Air Pollution Control Bureau (Chattanooga, TN). The bureau has evidence of LNOx-caused ozone-exceedances in the Chattanooga region, but has limited tools available to fully address the role of lightning. Hence, MSFC is planning to apply its Lightning Nitrogen Oxides Model (LNOM) to assist the bureau in better understanding exceedance attribution. Extensions of the same to a similar bureau in Birmingham, AL is intended.


INITIAL PROJECT ABSTRACT

Cloud-to-Ground lightning flash density

The evolution of the cloud-to-ground (CG) lightning flash density during the decade (2003-2012). There is a general downward trend in CG counts. Under a warming scenario, increases in CG frequency are expected, but lack of atmospheric moisture (e.g., the drought in 2012) can decrease CG frequency considerably.

Background:
The correlation between a warming climate and increases in: thunderstorm frequency, lightning, extreme weather events, tropospheric ozone (due to increased lightning nitrogen oxides), and other lightning-caused impacts (human injury/death, fire initiation,  crop/property damage, and power outages) are important concerns that have not been adequately monitored for purposes of decision planning, mitigation, and adaptation. Lightning observations suitable for NCA investigations were only fully available starting in ~2003, and so the first decade of assessment monitoring can now begin.

Proposed Effort:
This effort will routinely evaluate national lightning data, and several databases associated with the harmful impacts of lightning (i.e., fatalities, injuries, property/crop damage, wildfires) in order to generate insightful assessment products that contain analyses, trends, and alerts pertinent to a warming climate.  Therefore, the primary focus will be to produce assessment products using a NASA visualization tool that is useful in monitoring key climate-warming-induced changes in lightning, and that can be used to monitor and predict the impact of these changes on humankind. The effort will also analyze NASA satellite Lightning Imaging Sensor (LIS) data to inter-compare with the ground-based national lightning data analyses.

Results/Significance:
The work addresses key sections of the National Climate Assessment (NCA), including impacts to the Human Health, Agriculture, and Forestry sectors across all regions of CONUS, “Cross-Cutting” (extreme events), and “Human Responses” (disaster preparedness and risk-based approaches).

Project Publications:

Koshak, W. J., K. L. Cummins, D. E. Buechler, B. Vant-Hull, R. J. Blakeslee, E. R. Williams, H. S. Peterson, 2015: Variability of CONUS Lightning in 2003-12 and Associated Impacts, J. Appl. Meteorol. Climatology, 54, No. 1, 15-41. http://dx.doi.org/10.1175/JAMC-D-14-0072.1.

Koshak, W. J., and R. J. Solakiewicz, 2015: A method for retrieving the ground flash fraction and flash type from satellite lightning mapper observations, J. Atmos. Oceanic Technol., 32, No. 1,79-96.

Koshak, W. J., R. J. Solakiewicz, H. S. Peterson, 2015: A return stroke NOx production model, J. Atmos. Sci., 72, 943-954.

Chronis, T., K. Cummins, R. Said, W. J. Koshak, E. McCaul, E. R. Williams, G. T. Stano, and M. Grant, 2014: Climatological diurnal variation of negative CG lightning peak current over the continental United States, J. Geophys. Res. Atmos., 120, doi:10.1002/2014JD022547.

Buechler, D. E., W. J. Koshak, H. J. Christian, and S. J. Goodman, 2014: Assessing the performance of the Lightning Imaging Sensor (LIS) using deep convective clouds, Atmos. Res., 135-136, 397-403.

Beirle, S., W. J. Koshak, R. Blakeslee, and T. Wagner, 2014: Global patterns of lightning properties derived by OTD and LIS, Nat. Hazards Earth Syst. Sci., 14, 2715-2726, doi:10.5194/nhess-14-2715-2014.

Koshak, W. J., H. S. Peterson, A. P. Biazar, M. Khan, and L. Wang, 2014: The NASA Lightning Nitrogen Oxides Model (LNOM): application to air quality modeling, Atmos. Res., 135-136, 363-369.