| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | August 16, 2019 |
| Latest Amendment Date: | August 16, 2019 |
| Award Number: | 1917328 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Varavut (Var) Limpasuvan
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2019 |
| End Date: | August 31, 2022 (Estimated) |
| Total Intended Award Amount: | $203,042.00 |
| Total Awarded Amount to Date: | $203,042.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1251 MEMORIAL DR CORAL GABLES FL US 33146-2509 (305)421-4089 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Key Biscayne FL US 33149-1031 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Climate & Large-Scale Dynamics |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Just as medicine learns from biology's studies of fruit flies and lab mice, atmospheric sciences rely on a "hierarchy" of models with various complexity that allow the processes under the consideration to interact with one another fully while keeping others simplified for improving our understanding and enhancing our ability of weather and climate simulations and predictions. The vertical dimension of the atmosphere is special, because temperature and pressure vary greatly in just a few kilometers. Modeling of atmospheric vertical profiles under various conditions, called single-column model, has been regarded the lowest "root" of the hierarchy of model complexity for atmospheric sciences. The goal of this project is to develop and demonstrate the utility of using single-column model platform for understanding and evaluating impacts of various physical parameterization schemes on the tropical climate and variability of a climate model. This project will contribute to relevant international model intercomparison projects, such as the Radiative-Convective Equilibrium Model Intercomparison Project and the Global Atmospheric Systems Study - Weak Temperature Gradient project. The project will support a graduate student to complete his degree and the training of the next generation of atmospheric scientists is also an important impact of this project.
In this project, a PhD student will complete his multi-year work with the PI in devising a version of the Community Atmosphere Model that includes only the vertical interactions among radiation, surface energy exchanges, and turbulence and cloud processes. Specifically, they will configure the single-column model component of 4 versions of the Community Atmospheric Model in two different settings: one only considers interactions among radiative and convective processes and the other also includes large-scale dynamics effects, although highly idealized or parameterized, in the interaction loops. In the latter case, the large scale would be parameterized using either the weak temperature gradient approximation, or the damped-gravity wave limit. They will use this framework to explore the dependence of simulated column atmosphere on radiative heating rate, convective parameterizations, vertical resolution and forcing and its interactions with large-scale dynamics.
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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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 atmosphere is 3-dimensional system, but these dimensions are of different importance. The first and most important is the vertical dimension, which is the topic of this work. Treating the whole world as a Single Column of air allows many of the processes of weather to occur, because the very wide range of temperatures and altitudes are included, while setting aside some complications and distractions from the most fundamental issues. These fundamental processes like clouds and convection and radiation are key drivers of weather and climate, but are complicatedly mixed up with winds blowing things around. By ignoring the wind, or pretending it is an infinitely efficient efficient mixer or averager of information and conditions in the horizontal, we and future researchers can discover how fundamental processes interplay among each other, and try to improve how science views and computes these individual processes and their interactions. Atmospheric science's grand challenge is to predict as much as possible about the whole behavior of a system that may be more complex than our own brains, using only as much understandable simplification as suffices. Our study is a contribution toward that grand goal -- and more practically, it is also a contribution toward the process of model improvement, which broadly serves all other goals in the weather and climate enterprise.
Last Modified: 11/19/2022
Modified by: Brian E Mapes
Addendum # 1
An unexpected result of this vertical-column idealization of the atmosphere is shown in the image. In the two most recent model versions (5 and 6), very different multi-day variations are seen. Skies alternate between upper-level clear and cloudy conditions. Cloud layers descend with time, even though vertical air motion (the usual reason for day-to-day cloud variations) is artificially suppressed in a single column. These results show how interactions of a stable layer with convection, turbulence, moisture, cloudiness, and thermal radiation can surprise us -- even though each one of those processes is well understood separately by its (independent) designers.
By offering such insights, emergent phenomena like these oscillations can provide more holistic understanding and guidance to the development of better models. Lying between well-understood basic physical processes, and too-complicated-to-unpack real-world weather simulations, these insights show the value of a hierarchy of model-configuration complexity. Such a hierarchy is humanity's best hope to understand massively complex systems like the Earth's atmosphere.
Specifically, these results spotlight aspects of the model's deep convection scheme. Some of its unrealistic computational constraints are shown to be surprisingly important to its behavior, in ways that must also be affecting more-realistic (round-planet) simulations higher in the hierarchy. Among those unrealistic constraints is the neglect of organization of deep convective storms into thunderstorm groups. Other project work attempted to quantify this organization, in hopes it can be included in next-generation models. Also, more-refined single column models (allowed to interact with simplified vertical air motions) were shown to exhibit additional, different oscillations of unforeseeable character. Those results can further help to illuminate how limited sets of process interactions operature, better characterizing emergent model behaviors in hopes of driving or steering model improvement.
Added: 02/08/2023
Submitted by: Brian E Mapes
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