Reconstruction of the Broader Tropical Chimneys using TRMM-Retrieved Wilson Currents

16 March 2017

The baseline 20 km run of the Peterson et al. (2015) electric field retrieval algorithm on the Tropical Rainfall Measuring Mission (TRMM) dataset is used to rank the three tropical chimney regions. Unlike previous studies that have looked only at land-based thunderstorms, we consider thunderstorms and Electrified Shower Clouds (ESCs) in land and ocean regions across longitude quadrants that encompass each of the three chimneys – the Americas, Africa, and Asia – and the Pacific Ocean.

M. J. Peterson, W. Deierling, C. Liu, D. Mach, and C. Kalb

Geophysical Research Letters, PREPARING SUBMISSION

Picture Caption: 

Diurnal Cycle of Total Mean Current. Distributions of total mean Wilson currents across the tropics (solid, thick), the Americas (solid, thin), Africa, (dot-dashed), Asia (dashed), and the Pacific (dotted).

A TRMM Survey of Retrieved Electric Fields and Wilson Currents above Thunderstorms and Shower Clouds

16 March 2017

A database of Radar Precipitation Features (RPFs) is constructed for electrified clouds. This Electrified Cloud Features (ECF) database includes only those RPFs with pixels that the Tropical Rainfall Measuring Mission (TRMM) passive microwave electric field algorithm considers to be electrified (20 km electric fields > 0 Vm-1).

M. J. Peterson, W. Deierling, C. Liu, D. Mach, and C. Kalb

Journal of Geophysical Research, FINALIZING SUBMISSION

Picture Caption: 

CDF of GEC Contribution by Current. Distributions for thunderstorms (thick) and shower clouds (thin). Also, separately for land (solid), coastal ocean (dot-dashed), and open ocean (dashed)

A TRMM/GPM Retrieval of the Total Mean Generator Current for the Global Electric Circuit

16 March 2017

Retrieved electric fields from Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) satellite observations are used to calculate the total mean Wilson current that powers the Global Electric Circuit (GEC). The long record of TRMM data is also used to examine the temporal variability of the GEC source current on time scales that range from one day to more than a decade.

M. J. Peterson, W. Deierling, C. Liu, D. Mach, and C. Kalb

Picture Caption: 

Global GEC Current Sources. Global distribution of total mean Wilson currents from electrified weather as a fraction of the total for comparison with other metrics

Performance Assessment of the Passive Microwave Electric Field Retrieval Algorithm with TRMM Satellite Observations

16 March 2017

Peterson et al. (2015) developed an algorithm for estimating the electric field vector at any point above an electrified cloud from passive microwave observations. It is constructed using NASA ER-2 high-altitude aircraft electric field and passive microwave measurements. The present study constructs a version of the Peterson et al. (2015) algorithm for use with Precipitation Measurement Mission (PMM) satellite datasets.

M. J. Peterson, W. Deierling, C. Liu, D. Mach, and C. Kalb

Journal of Atmospheric and Oceanic Technology, UNDER REVIEW

Picture Caption: 

Example TRMM MCS. TMI 85 GHz brightness temperatures (top), and electric field strength and horizontal vectors (bottom).

The Properties of Optical Lightning Flashes and the Clouds They Illuminate

16 March 2017

Why do lightning flashes illuminate the clouds in the way they do? Some flashes produce bright stationary optical pulses that illuminate a large fraction of the storm. Others are dim and move around in the cloud as they evolve. The Lightning Imaging Sensor onboard the Tropical Rainfall Measuring Mission (TRMM) satellite surveyed lightning flashes of all shapes, sizes, and radiances across the tropics. Because LIS is an optical imager, however, it is unclear to what extent the observed characteristics of LIS flashes are influenced by scattering in the surrounding cloud.

M. J. Peterson, W. Deierling, C. Liu, D. Mach, and C. Kalb

Picture Caption: 

Example Propagating LIS Flash. Greyscale: LIS group number (grey: first group, white: last group). Color scale: VIRS 10.8 µm Tb.

A method of estimating electric fields above electrified clouds from passive microwave observations

16 March 2017

An algorithm is presented for estimating the total three-dimensional electric field vector at an arbitrary point over electrified weather from 37 GHz or 85 GHz passive microwave measurements. These frequencies are sensitive to column ice, which is important for electrification. The algorithm uses the geospatial distribution of ice mass as a proxy for charge accumulation across the microwave scene and then employs Coulomb’s Law to approximate the orientation and relative strength of the electric field vector that would be felt by an observer at a specified position and altitude.

M. J. Peterson, W. Deierling, C. Liu, D. Mach, and C. Kalb

Picture Caption: 

Example ER-2 Overflight. Electric fields measured by the field mills (thick line) are compared against the passive microwave estimates (thin line). The percent error is also shown (dotted line)

Characteristics of lightning flashes with exceptional illuminated areas, durations, and optical powers and surrounding storm properties in the tropics and inner subtropics

16 March 2017

While most optical flashes observed by the Lighting Imaging Sensor (LIS) are small, short-lived, and relatively dim, there are a number of exceptional flashes that can be noted in the LIS dataset. This study examines extreme lightning events and identifies the regions of the globe and the types of storms that produce them. We also incorporate ground-based radio lightning measurements from the National Lightning Detection Network to gain a better perspective on the discharge unmodified by the clouds.

M. J. Peterson and C. Liu

Picture Caption: 

The Largest LIS Flash. Yellow dots: LIS event pixels. Rings: LIS group ellipsoid fits. Color scale: VIRS 10.8 µm Tb

Global statistics of lightning in anvil and stratiform regions over the tropics and subtropics observed by TRMM

16 March 2017

Lightning is a natural hazard that is often associated with convective processes. Strong updrafts within the thunderstorm’s core provide a venue for different species of ice to collide and transfer electrons in the process. They also sort ice particles by mass, leading to charge separation and lightning production. Lightning can occur outside of the convective core, however. This study uses Tropical Rainfall Measuring Mission (TRMM) observations to identify lightning flashes in anvil and stratiform regions of thunderstorms across the tropics.

M. J. Peterson and C. Liu

Picture Caption: 

Storm with Anvil/Stratiform Flashes. Plusses: LIS flash centroids. Color scale: TRMM PR rain type (conv., strat., anvil).

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