Lightning distribution and its association with surface thermodynamics parameters over a western Himalayan region.

The analysis of Tropical Rainfall Measuring Mission-Lightning Imaging Sensor (TRMM-LIS) datasets indicates that lightning distribution in Uttarakhand significantly varies with elevation, peaking in the Himalayan foothills below 1500 m and decreasing above 4000 m. Furthermore, moderate (SLI 1–2) and mild (SLI 0–1) lightning hotspots have been identified in Uttarakhand. The monthly variations in lightning flash rate density (LFRD) and surface meteorological parameters show a moderate correlation of <0.6. However, the lag of 1 to 3 months in the meteorological parameter peak values from LFRD peak values does not support the cause-and-effect relation between them. However, LFRD is better correlated (r = 0.97) with the sensible heat fluxes (SHF). We found that the product of the Bowen ratio (BR) and convective rain rate (CRR) can serve as a good representative of lightning over this region. Principal component analysis (PCA) of the data reveals a strong relationship between LFRD and SHF, BR, the product of BR and CRR, maximum surface temperature (MST), CAPE, humidity, and CRR, emphasizing the impact of strong land surface heating, air parcel buoyancy, and deep convection on lightning. Cloud base height and latent heat flux (LHF) have weak correlations with LFRD. Eigenvalue loadings analysis indicated that CAPE, MST, humidity, and CRR are dominant factors in principal component (PC) PC1, while LFRD, BR, SHF, and the product of BR and CRR are dominant factors in PC2, influencing lightning over this region. This study offers valuable insights into the lightning distribution over Uttarakhand and its relationship with meteorological, topographical, and thermodynamic variables. [ABSTRACT FROM AUTHOR]