Abstract Gridded climatologies of total lightning flash rates observed by the spaceborne Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) instruments have been updated. OTD collected data from May 1995 to March 2000. LIS data (equatorward of about 38°) adds the years 1998–2010. Flash counts from each instrument are scaled by the best available estimates of detection efficiency. The long LIS record makes the merged climatology most robust in the tropics and subtropics, while the high latitude data is entirely from OTD. The gridded climatologies include annual mean flash rate on a 0.5° grid, mean diurnal cycle of flash rate on a 2.5° grid with 24 hour resolution, mean annual cycle of flash rate on a 0.5° or 2.5° grid with daily, monthly, or seasonal resolution, mean annual cycle of the diurnal cycle on a 2.5° grid with two hour resolution for each day, and time series of flash rate over the sixteen year record with roughly three-month smoothing. For some of these (e.g., annual cycle of the diurnal cycle), more smoothing is necessary for results to be robust. The mean global flash rate from the merged climatology is 46 flashes s− 1. This varies from around 35 flashes s− 1 in February (austral summer) to 60 flashes s− 1 in August (boreal summer). The peak annual flash rate at 0.5° scale is 160 fl km− 2 yr− 1 in eastern Congo. The peak monthly average flash rate at 2.5° scale is 18 fl km− 2 mo− 1 from early April to early May in the Brahmaputra Valley of far eastern India. Lightning decreases in this region during the monsoon season, but increases further north and west. An August peak in northern Pakistan also exceeds any monthly averages from Africa, despite central Africa having the greatest yearly average.
[1]
R. Orville,et al.
Global Lightning Flash Frequency
,
1979
.
[2]
F. Whipple.
On the association of the diurnal variation of electric potential gradient in fine weather with the distribution of thunderstorms over the globe
,
2007
.
[3]
Richard J. Blakeslee,et al.
Performance Assessment of the Optical Transient Detector and Lightning Imaging Sensor. Part I: Predicted Diurnal Variability
,
2002
.
[4]
H. Christian.
Global Frequency and Distribution of Lightning as Observed From Space
,
2001
.
[5]
Robert F. Adler,et al.
A Ten-Year Tropical Rainfall Climatology Based on a Composite of TRMM Products
,
2009
.
[6]
M. Darveniza,et al.
Global lightning: Total, cloud and ground flash estimates
,
1998
.
[7]
C. A. Hernandez.
The QBO's influence on lightning production in the Tropics
,
2008
.
[8]
Richard J. Blakeslee,et al.
The 13 years of TRMM Lightning Imaging Sensor: From individual flash characteristics to decadal tendencies
,
2011
.
[9]
D. Cecil,et al.
Toward a Global Climatology of Severe Hailstorms as Estimated by Satellite Passive Microwave Imagers
,
2012
.
[10]
T. N. Krishnamurti,et al.
The status of the tropical rainfall measuring mission (TRMM) after two years in orbit
,
2000
.
[11]
Richard J. Blakeslee,et al.
Seasonal variations in the lightning diurnal cycle and implications for the global electric circuit
,
2014
.
[12]
M. G. Nicora,et al.
Characterization of the lightning activity of ''Relampago del Catatumbo''
,
2012
.