scholarly journals What Are the Favorable Large-Scale Environments for the Highest-Flash-Rate Thunderstorms on Earth?

2020 ◽  
Vol 77 (5) ◽  
pp. 1583-1612 ◽  
Author(s):  
Nana Liu ◽  
Chuntao Liu ◽  
Baohua Chen ◽  
Edward Zipser
Keyword(s):  
Wind Shear ◽  
Large Scale ◽  
Convective Available Potential Energy ◽  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
Lightning Flash ◽  
Tropical Regions ◽  
Flash Rate ◽  
South Central ◽  
Sahel Region

Abstract A 16-yr Tropical Rainfall Measuring Mission (TRMM) convective feature (CF) dataset and ERA-Interim data are used to understand the favorable thermodynamic and kinematic environments for high-flash-rate thunderstorms globally as well as regionally. We find that intense thunderstorms, defined as having more than 50 lightning flashes within a CF during the ~90-s TRMM overpassing time share a few common thermodynamic features over various regions. These include large convective available potential energy (>1000 J kg−1), small to moderate convection inhibition (CIN), and abundant moisture convergence associated with low-level warm advection. However, each region has its own specific features. Generally, thunderstorms with high lightning flash rates have greater CAPE and wind shear than those with low flash rates, but the differences are much smaller in tropical regions than in subtropical regions. The magnitude of the low- to midtropospheric wind shear is greater over the subtropical regions, including the south-central United States, Argentina, and southwest of the Himalayas, than tropical regions, including central Africa, Colombia, and northwest Mexico, with the exception of Sahel region. Relatively, favorable environments of high-flash-rate thunderstorms in the tropical regions are characterized by higher CAPE, lower CIN, and weaker wind shear compared to the high-flash-rate thunderstorms in the subtropical regions, which have a moderate CAPE and CIN, and stronger low to midtropospheric wind shear.

scholarly journals TRMM LIS Climatology of Thunderstorm Occurrence and Conditional Lightning Flash Rates*

2015 ◽  
Vol 28 (16) ◽  
pp. 6536-6547 ◽  
Author(s):  
Daniel J. Cecil ◽  
Dennis E. Buechler ◽  
Richard J. Blakeslee
Keyword(s):  
East Coast ◽  
Eastern China ◽  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
Lightning Flash ◽  
Conditional Mean ◽  
Flash Rate ◽  
Central United States ◽  
Total Lightning ◽  
Imaging Sensor

Abstract The Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite has previously been used to build climatologies of mean lightning flash rate across the global tropics and subtropics. This new work explores climatologies of thunderstorm occurrence as seen by LIS and the conditional mean flash rates when thunderstorms do occur. The region where thunderstorms are seen most often by LIS extends slightly farther east in central Africa than the corresponding region with the highest total mean annual flash rates. Presumably this reflects a difference between more frequent thunderstorm initiation in the east and upscale growth as storms move westward. There are some differences between locations with the greatest total lightning flash counts and those where thunderstorms occur most often. The greatest conditional mean flash rates—considering only those TRMM orbits that do have lightning in a given grid box—are found in subtropical regions. The highest values are in Argentina, with the central United States, Pakistan, eastern China, and the east coast of Australia also having particularly high values.

scholarly journals The climate impact of aerosols on the lightning flash rate: is it detectable from long-term measurements?

2018 ◽  
Vol 18 (17) ◽  
pp. 12797-12816 ◽  
Author(s):  
Qianqian Wang ◽  
Zhanqing Li ◽  
Jianping Guo ◽  
Chuanfeng Zhao ◽  
Maureen Cribb
Keyword(s):  
Convective Available Potential Energy ◽  
Central Africa ◽  
Vertical Wind Shear ◽  
Climate Impact ◽  
Northern Africa ◽  
Lightning Flash ◽  
Flash Rate ◽  
Aerosol Loading ◽  
Aerosol Type

Abstract. The effect of aerosols on lightning has been noted in many case studies, but much less is known about the long-term impact, relative importance of dynamics–thermodynamics versus aerosol, and any difference by different types of aerosols. Attempts are made to tackle all these factors, whose distinct roles are discovered by analyzing 11-year datasets of lightning, aerosol loading and composition, and dynamic–thermodynamic data from satellite and model reanalysis. Variations in the lightning rate are analyzed with respect to changes in dynamic–thermodynamic variables and indices such as the convective available potential energy (CAPE) and vertical wind shear. In general, lightning has strong diurnal and seasonal variations, peaking in the afternoon and during the summer. The lightning flash rate is much higher in moist central Africa than in dry northern Africa presumably because of the combined influences of surface heating, CAPE, relative humidity (RH), and aerosol type. In both regions, the lightning flash rate changes with aerosol optical depth (AOD) in a boomerang shape: first increasing with AOD, tailing off around AOD  =  0.3, and then behaving differently, i.e., decreasing for dust and flattening for smoke aerosols. The deviation is arguably caused by the tangled influences of different thermodynamics (in particular humidity and CAPE) and aerosol type between the two regions. In northern Africa, the two branches of the opposite trends seem to echo the different dominant influences of the aerosol microphysical effect and the aerosol radiative effect that are more pronounced under low and high aerosol loading conditions, respectively. Under low-AOD conditions, the aerosol microphysical effect more likely invigorates deep convection. This may gradually yield to the suppression effect as AOD increases, leading to more and smaller cloud droplets that are highly susceptible to evaporation under the dry conditions of northern Africa. For smoke aerosols in moist central Africa, the aerosol invigoration effect can be sustained across the entire range of AOD by the high humidity and CAPE. This, plus a potential heating effect of the smoke layer, jointly offsets the suppression of convection due to the radiative cooling at the surface by smoke aerosols. Various analyses were done that tend to support this hypothesis.

scholarly journals Tropical Cyclone Count Forecasting Using a Dynamical Seasonal Prediction System: Sensitivity to Improved Ocean Initialization

2011 ◽  
Vol 24 (12) ◽  
pp. 2963-2982 ◽  
Author(s):  
Andrea Alessandri ◽  
Andrea Borrelli ◽  
Silvio Gualdi ◽  
Enrico Scoccimarro ◽  
Simona Masina
Keyword(s):  
Tropical Cyclone ◽  
Indian Ocean ◽  
Wind Shear ◽  
Large Scale ◽  
Initial Conditions ◽  
North Pacific Ocean ◽  
Convective Available Potential Energy ◽  
Seasonal Prediction ◽  
Boreal Summer ◽  
Prediction System

Abstract This study investigates the predictability of tropical cyclone (TC) seasonal count anomalies using the Centro Euro-Mediterraneo per i Cambiamenti Climatici–Istituto Nazionale di Geofisica e Vulcanologia (CMCC-INGV) Seasonal Prediction System (SPS). To this aim, nine-member ensemble forecasts for the period 1992–2001 for two starting dates per year were performed. The skill in reproducing the observed TC counts has been evaluated after the application of a TC location and tracking detection method to the retrospective forecasts. The SPS displays good skill in predicting the observed TC count anomalies, particularly over the tropical Pacific and Atlantic Oceans. The simulated TC activity exhibits realistic geographical distribution and interannual variability, thus indicating that the model is able to reproduce the major basic mechanisms that link the TCs’ occurrence with the large-scale circulation. TC count anomalies prediction has been found to be sensitive to the subsurface assimilation in the ocean for initialization. Comparing the results with control simulations performed without assimilated initial conditions, the results indicate that the assimilation significantly improves the prediction of the TC count anomalies over the eastern North Pacific Ocean (ENP) and northern Indian Ocean (NI) during boreal summer. During the austral counterpart, significant progresses over the area surrounding Australia (AUS) and in terms of the probabilistic quality of the predictions also over the southern Indian Ocean (SI) were evidenced. The analysis shows that the improvement in the prediction of anomalous TC counts follows the enhancement in forecasting daily anomalies in sea surface temperature due to subsurface ocean initialization. Furthermore, the skill changes appear to be in part related to forecast differences in convective available potential energy (CAPE) over the ENP and the North Atlantic Ocean (ATL), in wind shear over the NI, and in both CAPE and wind shear over the SI.

The Origin, Formation and Early History of the Chikunda of South Central Africa

1972 ◽  
Vol 13 (3) ◽  
pp. 443-461 ◽  
Author(s):  
Allen Isaacman
Keyword(s):  
Nineteenth Century ◽  
Historical Linguistic ◽  
Cultural Differences ◽  
Ethnic Groups ◽  
Large Scale ◽  
Central Africa ◽  
Military History ◽  
Early History ◽  
South Central ◽  
History Of

Although historians have examined the process of pre-colonial political integration, little attention has been paid to the complementary patterns of ethnic and cultural assimilation. The Chikunda, who were initially slaves on the Zambezi prazos, provide an excellent example of this phenomenon. Over the course of several generations, captives from more than twenty ethnic groups submerged their historical, linguistic, and cultural differences to develop a new set of institutions and a common identity. The decline of the prazo system during the first half of the nineteenth century generated large scale migrations of Chikunda outside of the lower Zambezi valley. They settled in Zumbo, the Luangwa valley and scattered regions of Malawi where they played an important role in the nineteenth-century political and military history of south central Africa.

scholarly journals Using cloud ice flux to parametrise large-scale lightning

2014 ◽  
Vol 14 (12) ◽  
pp. 17817-17856 ◽  
Author(s):  
D. L. Finney ◽  
R. M. Doherty ◽  
O. Wild ◽  
H. Huntrieser ◽  
H. C. Pumphrey ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Tropical Rainfall Measuring Mission ◽  
Reanalysis Data ◽  
Lightning Flash ◽  
Spatial Correlations ◽  
Zonal Distribution ◽  
Annual Total ◽  
Cloud Ice ◽  
Mean Square Errors

Abstract. Lightning is an important natural source of nitrogen oxide especially in the middle and upper troposphere. Hence, it is essential to represent lightning in chemistry transport and coupled chemistry-climate models. Using ERA-Interim meteorological reanalysis data we compare the lightning flash density distributions produced using several existing lightning parametrisations, as well as a new parametrisation developed on the basis of upward cloud ice flux at 440 hPa. The use of ice flux forms a link to the non-inductive charging mechanism of thunderstorms. Spatial and temporal distributions of lightning flash density are compared to tropical and subtropical observations for 2007–2011 from the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission satellite. The well-used lightning flash parametrisation based on cloud-top height has large biases but the derived annual total flash density has a better spatial correlation with the LIS observations than other existing parametrisations. A comparison of flash density simulated by the different schemes shows that the cloud-top height parametrisation has many more instances of moderate flash densities and fewer low and high extremes compared to the other parametrisations. Other studies in the literature have shown that this feature of the cloud-top height parametrisation is in contrast to lightning observations over certain regions. Our new ice flux parametrisation shows a clear improvement over all the existing parametrisations with lower root mean square errors and better spatial correlations with the observations for distributions of annual total, and seasonal and interannual variations. The greatest improvement with the new parametrisation is a more realistic representation of the zonal distribution with a better balance between tropical and subtropical lightning flash estimates. The new parametrisation is appropriate for testing in chemistry transport and chemistry-climate models that use a lightning parametrisation.

scholarly journals Improving Geostationary Satellite Rainfall Estimates Using Lightning Observations: Underlying Lightning–Rainfall–Cloud Relationships

2013 ◽  
Vol 52 (1) ◽  
pp. 213-229 ◽  
Author(s):  
Weixin Xu ◽  
Robert F. Adler ◽  
Nai-Yu Wang
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Heavy Rain ◽  
Heavy Precipitation ◽  
Convective System ◽  
Specific Rate ◽  
Lightning Flash ◽  
Convective Rainfall ◽  
Light Rain ◽  
Flash Rate ◽  
Pixel Scale

AbstractThis study quantifies the relationships among lightning activity, convective rainfall, and associated cloud properties on both convective-system scale (or storm scale) and satellite-pixel scale (~5 km) on the basis of 13 yr of Tropical Rainfall Measuring Mission measurements of rainfall, lightning, and clouds. Results show that lightning frequency is a good proxy to separate storms of different intensity, identify convective cores, and screen out false convective-core signatures in areas of thick anvil debris. Significant correlations are found between storm-scale lightning parameters and convective rainfall for systems over the southern United States, the focus area of the study. Storm-scale convective rainfall or heavy-precipitation area has the best correlation (coefficient r = 0.75–0.85) with lightning-flash area. It also increases linearly with increasing lightning-flash rate, although correlations between convective/heavy rainfall and lightning-flash rate are somewhat weaker (r = 0.55–0.75). Statistics further show that active lightning and intense precipitation are not well collocated on the pixel scale (5 km); for example, only 50% of the lightning flashes are coincident with heavy-rain cores, and more than 20% are distributed in light-rain areas. Simple positive correlations between lightning-flash rate and precipitation intensity are weak on the pixel scale. Lightning frequency and rain intensity have positive probabilistic relationships, however: the probability of heavy precipitation, especially on a coarser pixel scale (~20 km), increases with increasing lightning-flash density. Therefore, discrete thresholds of lightning density could be applied in a rainfall estimation scheme to assign precipitation in specific rate categories.

Thermodynamic Contribution to Lightning Activity in the Fourth Chimney

2021 ◽  
Author(s):  
Earle Williams ◽  
Diego Enore ◽  
Enrique Mattos ◽  
Yen-Jung Joanne Wu
Keyword(s):  
Convective Available Potential Energy ◽  
Lightning Activity ◽  
South Pacific Convergence Zone ◽  
Convergence Zone ◽  
Lightning Flash ◽  
Schumann Resonance ◽  
Flash Rate ◽  
Zonal Wavenumber ◽  
Usual Behavior ◽  
Total Lightning

<p>Lightning activity over oceans is normally greatly suppressed in comparison with continents.  The most conspicuous region of enhanced lightning activity over open ocean is found in the equatorial Pacific (150 W) in many global lightning climatologies (OTD, LIS, WWLLN, GLD360, RHESSI, Schumann resonance Q-bursts) and is associated with the South Pacific Convergence Zone (SPCZ).  This oceanic lightning anomaly completes the zonal wavenumber-4 structure of continent-based lightning maxima (with nominal 90-degree longitudinal separation between sources), and so is appropriately named “the fourth chimney”.  This region is now under continuous surveillance by the Geostationary Lightning Mapper (GLM) on the GOES-17 satellite (at 137 W).  This total lightning activity is compared with Convective Available Potential Energy (CAPE) from ERA-5 reanalysis.  These CAPE values are correlated with values extracted from thermodynamic soundings at proximal stations Atuona, Rikitea and Tahiti.  The shape of the regional climatology of CAPE resembles that of the SPCZ and is oblique to the equator.  The total lightning flash rate is positively correlated with CAPE, and lightning locations are found preferentially in regions of elevated CAPE on individual days.  The diurnal variation of total lightning for January exceeds a factor-of-two and shows a phase at odds with the usual behavior of oceanic lightning near continents.</p>

scholarly journals Using cloud ice flux to parametrise large-scale lightning

2014 ◽  
Vol 14 (23) ◽  
pp. 12665-12682 ◽  
Author(s):  
D. L. Finney ◽  
R. M. Doherty ◽  
O. Wild ◽  
H. Huntrieser ◽  
H. C. Pumphrey ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Tropical Rainfall Measuring Mission ◽  
Reanalysis Data ◽  
Lightning Flash ◽  
Spatial Correlations ◽  
Zonal Distribution ◽  
Annual Total ◽  
Cloud Ice ◽  
Mean Square Errors

Abstract. Lightning is an important natural source of nitrogen oxide especially in the middle and upper troposphere. Hence, it is essential to represent lightning in chemistry transport and coupled chemistry–climate models. Using ERA-Interim meteorological reanalysis data we compare the lightning flash density distributions produced using several existing lightning parametrisations, as well as a new parametrisation developed on the basis of upward cloud ice flux at 440 hPa. The use of ice flux forms a link to the non-inductive charging mechanism of thunderstorms. Spatial and temporal distributions of lightning flash density are compared to tropical and subtropical observations for 2007–2011 from the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite. The well-used lightning flash parametrisation based on cloud-top height has large biases but the derived annual total flash density has a better spatial correlation with the LIS observations than other existing parametrisations. A comparison of flash density simulated by the different schemes shows that the cloud-top height parametrisation has many more instances of moderate flash densities and fewer low and high extremes compared to the other parametrisations. Other studies in the literature have shown that this feature of the cloud-top height parametrisation is in contrast to lightning observations over certain regions. Our new ice flux parametrisation shows a clear improvement over all the existing parametrisations with lower root mean square errors (RMSEs) and better spatial correlations with the observations for distributions of annual total, and seasonal and interannual variations. The greatest improvement with the new parametrisation is a more realistic representation of the zonal distribution with a better balance between tropical and subtropical lightning flash estimates. The new parametrisation is appropriate for testing in chemistry transport and chemistry–climate models that use a lightning parametrisation.

Three Years of TRMM Precipitation Features. Part I: Radar, Radiometric, and Lightning Characteristics

2005 ◽  
Vol 133 (3) ◽  
pp. 543-566 ◽  
Author(s):  
Daniel J. Cecil ◽  
Steven J. Goodman ◽  
Dennis J. Boccippio ◽  
Edward J. Zipser ◽  
Stephen W. Nesbitt
Keyword(s):  
Brightness Temperature ◽  
Tropical Rainfall Measuring Mission ◽  
Radar Reflectivity ◽  
Lightning Flash ◽  
Frequency Of Occurrence ◽  
Areal Extent ◽  
Flash Rate ◽  
Brightness Temperatures ◽  
Rate Minimum ◽  
Trmm Precipitation

Abstract During its first three years, the Tropical Rainfall Measuring Mission (TRMM) satellite observed nearly six million precipitation features. The population of precipitation features is sorted by lightning flash rate, minimum brightness temperature, maximum radar reflectivity, areal extent, and volumetric rainfall. For each of these characteristics, essentially describing the convective intensity or the size of the features, the population is broken into categories consisting of the top 0.001%, top 0.01%, top 0.1%, top 1%, top 2.4%, and remaining 97.6%. The set of “weakest/smallest” features composes 97.6% of the population because that fraction does not have detected lightning, with a minimum detectable flash rate of 0.7 flashes (fl) min−1. The greatest observed flash rate is 1351 fl min−1; the lowest brightness temperatures are 42 K (85 GHz) and 69 K (37 GHz). The largest precipitation feature covers 335 000 km2, and the greatest rainfall from an individual precipitation feature exceeds 2 × 1012 kg h−1 of water. There is considerable overlap between the greatest storms according to different measures of convective intensity. The largest storms are mostly independent of the most intense storms. The set of storms producing the most rainfall is a convolution of the largest and the most intense storms. This analysis is a composite of the global Tropics and subtropics. Significant variability is known to exist between locations, seasons, and meteorological regimes. Such variability will be examined in Part II. In Part I, only a crude land–ocean separation is made. The known differences in bulk lightning flash rates over land and ocean result from at least two differences in the precipitation feature population: the frequency of occurrence of intense storms and the magnitude of those intense storms that do occur. Even when restricted to storms with the same brightness temperature, same size, or same radar reflectivity aloft, the storms over water are considerably less likely to produce lightning than are comparable storms over land.

scholarly journals Spatio-temporal Variability of Lightning Climatology and Its Association With Thunderstorm Indices Over India

2022 ◽  
Author(s):  
Unashish Mondal ◽  
Subrat Kumar Panda ◽  
Someshwar Das ◽  
Devesh Sharma
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Eastern Region ◽  
Lightning Flash ◽  
Time Duration ◽  
Jammu And Kashmir ◽  
Flash Rate ◽  
North Eastern ◽  
Very High Spatial Resolution ◽  
Spatio Temporal ◽  
Imaging Sensor

Abstract Lightning is an electrical discharge - a'spark' or 'flash' as charged regions in the atmosphere instantly balance themselves through this discharge. It is a beautiful and deadly naturally occurring phenomenon. In June 2020, more than a hundred people died in the state Bihar of India only in three days’ span due to lightning events. In this work, Lightning Imaging Sensor (LIS) information from the Tropical Rainfall Measuring Mission (TRMM) satellite with a very high spatial resolution of 0.1 X 0.1 degree has been utilized to create the climatology of India for 16 years from 1998 to 2013. Diurnal, monthly, and seasonal variations in the occurrence of lightning flash rate density have also been analyzed. TRMM satellite low-resolution monthly time series (LRMTS) with 2.5-degree resolution datasets have been used for lightning trend analysis. The diurnal lightning event mainly occurs in the afternoon/evening (1400-1900 Hrs) time duration around 0.001 flashes/km2/hr. The highest lightning occurred in May (0.04 flashes/km2/day) and the least in December (0.005 flashes/km2/day). The distribution of lightning flash counts by season over India landmass is mainly in pre-monsoon (MAM) ranges from 0.248 – 0.491 flashes/km2/day, and monsoon (JJA) ranges from 0.284 – 0.451 flashes/km2/day and decreases afterward. Spatially, the distribution of lightning flashes mainly at North-Eastern region along with Bangladesh, Bihar, Jharkhand, Orissa, and Jammu & Kashmir region. The CAPE and K Index have positively correlated with the flash rate density seasonally but CAPE is more significantly correlated. This study also focused on finding of lightning hotspots region of India district wise and Rajouri district in Jammu and Kashmir got the highest lightning with 121 flashes/km2/yr.

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