Award Abstract # 2034817
Organization of Tropical East Pacific Convection (OTREC) - Post-Campaign Analysis

NSF Org: AGS
Division of Atmospheric and Geospace Sciences
Recipient: NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY
Initial Amendment Date: January 25, 2021
Latest Amendment Date: May 20, 2021
Award Number: 2034817
Award Instrument: Standard Grant
Program Manager: Eric DeWeaver
edeweave@nsf.gov
 (703)292-8527
AGS
 Division of Atmospheric and Geospace Sciences
GEO
 Directorate for Geosciences
Start Date: March 1, 2021
End Date: February 28, 2025 (Estimated)
Total Intended Award Amount: $538,727.00
Total Awarded Amount to Date: $538,727.00
Funds Obligated to Date: FY 2021 = $538,727.00
History of Investigator:
  • Zeljka Stone (Principal Investigator)
    zeljka.fuchs@nmt.edu
  • David Raymond (Co-Principal Investigator)
Recipient Sponsored Research Office: New Mexico Institute of Mining and Technology
801 LEROY PL
SOCORRO
NM  US  87801-4681
(575)835-5496
Sponsor Congressional District: 02
Primary Place of Performance: New Mexico Institute of Mining and Technology
801 Leroy Place
Socorro
NM  US  87801-4681
Primary Place of Performance
Congressional District:
02
Unique Entity Identifier (UEI): HZJ2JZUALWN4
Parent UEI:
NSF Program(s): Climate & Large-Scale Dynamics
Primary Program Source: 01002122DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 9150
Program Element Code(s): 574000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

This award supports analysis of observations collected during the Organization of Tropical East Pacific Convection (OTREC) field campaign. The campaign was designed to study the formation and development of tropical convective clouds and associated heavy rainfall in the adjacent but distinct regions of the eastern equatorial Pacific and the southwest Caribbean, along with their evolution over the intervening portions of Central America and Colombia. The campaign also considered the genesis and evolution of easterly waves, large westward-moving atmospheric disturbances (wavelengths of about 2,000 km) which occur on a weekly basis in the Caribbean and eastern Pacific.

The campaign deployment, based in western Costa Rica, took place from August to October 2019 and featured 22 flights of the Gulfstream V research aircraft maintained by the National Center for Atmospheric Research. The aircraft flew at about 40,000 feet using dropsondes and a W-band radar to make observations of clouds and atmospheric conditions. Dropsondes contain the same instrument package as standard weather balloons, only dropped from the aircraft with a small parachute. The radar determines cloud properties including the concentrations of ice particles and liquid droplets, and uses Doppler shift to measure cloud updraft and downdraft speeds. The aircraft sampling was augmented by observations collected at ground sites in Costa Rica and Colombia.

This project continues the campaign's effort to identify the mechanisms that lead to the development of deep tropical convection. Much of the work is devoted to analysis of vertical mass flux profiles in convecting regions, in paticular whether rising motions in clouds occur in the lower to middle troposphere or the upper troposphere. The work is motivated by a theory of tropical convection developed by the Principle Investigators and others which emphasizes the association between bottom-heavy vertical mass flux profiles and heavy rainfall, as well as an inverse relationship between atmospheric stability and moisture content. Work here determines the extent to which the theory applies to all the OTREC study regions despite their differences in sea surface temperature and other conditions.

The project also considers whether easterly waves found in the eastern Pacific form locally or if they are the same easterly waves seen propagating across the Atlantic after forming in West Africa. Additional work considers the impact of the Madden-Julian Oscillation (MJO), a large-scale topical weather pattern, on convection observed during the campaign. The MJO caused a shift in low-level wind direction during the campaign and the effects of the wind shift on convection are not yet clear. Finally, the research includes collaborations with the European Centre for Medium-range Weather Forecasts to evaluate weather forecasts in the OTREC study area, and with colleagues at the National University of Colombia who bring surface-based observations and regional expertise to the project.

The work is of societal interest due to the importance of tropical convection for weather and climate across the globe. Easterly waves are of particular interest for weather forecasting given their tendency to spawn hurricanes. Better understanding of tropical convection and easterly waves is thus of interest for the improvement of weather and climate models and for helping decision makers anticipate the likely consequences of climate variability and change. The work also promotes international collaboration in atmospheric science through the collaborations mentioned above. The Principle Investigators pursue education and outreach through public lectures, a class on the "Science of Weather" for high school science teachers, and interactions with K-12 students. The project provides support and training to a graduate student and an undergraduate.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Fuchs-Stone, eljka and Emanuel, Kerry "Sensitivity of Linear Models of the MaddenJulian Oscillation to Convective Representation" Journal of the Atmospheric Sciences , v.79 , 2022 https://doi.org/10.1175/JAS-D-21-0165.1 Citation Details
Raymond, D. J. and FuchsStone, . "Weak Temperature Gradient Modeling of Convection in OTREC" Journal of Advances in Modeling Earth Systems , v.13 , 2021 https://doi.org/10.1029/2021MS002557 Citation Details
Raymond, D J and Stone, and Senti, S "Rains and Showers in OTREC; Weak Temperature Gradient Modeling" Journal of Advances in Modeling Earth Systems , v.16 , 2024 https://doi.org/10.1029/2023MS003980 Citation Details
Senti, Stipo and Bechtold, Peter and Fuchs-Stone, eljka and Rodwell, Mark and Raymond, David J. "On the impact of dropsondes on the ECMWF Integrated Forecasting System model (CY47R1) analysis of convection during the OTREC (Organization of Tropical East Pacific Convection) field campaign" Geoscientific Model Development , v.15 , 2022 https://doi.org/10.5194/gmd-15-3371-2022 Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

The field project Organization of Tropical East Pacific Convection (OTREC) took place in 2019. Various data was collected over the East Pacific and Southwest Caribbean that captured all phases of convection. This region was picked because of the diversity in its environment. The goal was to study all types of convection, to test existing theories and develop new ones.

The collected data set included dropsondes, Hiaper Cloud Radar measurements, radiosondes from 3 non-standard locations in Costa Rica and Colombia, intensified radiosonde launches from standard locations in Colombia and weather and global positioning system column water vapor.

More specifically OTREC and this project aimed to find what controls deep atmospheric convection in the OTREC region by focusing on the vertical mass flux profiles, the thermodynamic forcing mechanisms and thermodynamic budgets. We used modeling, cloud resolving model using the weak temperature gradient (WTG) approximation, WRF and ECMWF analysis as well. We found that ECMWF model produced more accurate forecast when it assimilated data from OTREC. This was in particular shown in winds profiles that are used to calculate vorticity and divergence and therefore very relevant.  

Answering the decades long question on what governs convection and how it can ultimately be represented in the models is of great importance in improving weather models.

We found that thermodynamic parameters such as saturation fraction and instability index show more correlation with deep convection and precipitation than standardly used temperature or humidity profiles. Furthermore, we found that convection regimes after being stripped of stratiform convection can be divided in two categories: showers and rains. Those categories have different characteristics which brings us closer to more accurate cumulus parametrizations.

OTREC data and its findings are incorporated in the class at New Mexico Tech for students who are obtaining their Master’s degree in Science for teachers. That way, indirectly, new findings reach K-12 students all over the US.

 


Last Modified: 04/02/2025
Modified by: Zeljka Stone

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