| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
|
| Initial Amendment Date: | January 25, 2021 |
| Latest Amendment Date: | May 20, 2021 |
| Award Number: | 2033467 |
| 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: | February 1, 2021 |
| End Date: | January 31, 2024 (Estimated) |
| Total Intended Award Amount: | $574,359.00 |
| Total Awarded Amount to Date: | $574,359.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
5801 S ELLIS AVE CHICAGO IL US 60637-5418 (773)702-8669 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
5734 S Ellis Ave Chicago IL US 60637-2612 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Climate & Large-Scale Dynamics |
| Primary Program Source: |
|
| Program Reference Code(s): | |
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The Earth's climate is a product of heat transfer, as the warming effect of heat energy gains, including the latent heat released in precipitation, must over time be balanced by equal heat losses to achieve a persistent climate state in any given region. An atmospheric column can transfer heat energy through its top and bottom by radiation, for instance when it cools by emitting infrared radiation to space, and by evaporation and thermal conduction at the Earth's surface. Lateral heat transfer is also critical, as in the tropics the Earth receives more energy from the sun than it radiates back to space and the opposite is true near the poles. Thus the tropics must export heat energy to the poles to balance the budgets of both regions.
Work under this award seeks to understand atmospheric heat transfer in low, middle, and high latitudes, considering both changes in heat transfer over the the seasonal cycle and differences in heat transfer between warmer and colder climates. For example simulations of modern climate show strong seasonal variations in latitudinal heat balances, with radiation largely balancing local evaporation and surface heat conduction in the middle latitudes of the Northern Hemisphere in summer, while lateral heat transfer is more prominent in other seasons. The situation is quite different in simulations of the "snowball earth" climate, where lateral transfer is prominent throughout the year over most of the globe. The underlying mechanisms that determine atmospheric heat balances in different climates, and drive changes in heat balances during transitions between climate states, are explored through analysis of existing simulations and through novel simulations using a variety of model configurations.
Heat transport plays an essential role in maintaining Earth's climate, and research on the topic has societal value given the need to better understand how the climate system works and how it is likely to change under the influence of greenhouse gas increases and changes in aerosol pollution. The project also provides support and training for a graduate student and an undergraduate, the latter recruited through a campus-wide program dedicated to increasing participation of underrepresented minorities in scientific research.
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
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
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 Earth’s climate and its response to climate change is controlled by distinct forms of energy transfer, including by radiation, advection (bulk movement of the fluid horizontally) and convection (bulk movement of the fluid vertically). The importance of different forms of energy transfer varies in space, particularly in laltitude and can change in time both seasonally and into the future under climate change. This project focused on quantifying the forms of energy transfer in the current climate and using that to understand the response to climate change. On seasonal timescales the results showed that in the tropics the dominant balance is between radiation and convection whereas over the pole the dominant balance is between radiation and advection. Seasonal transitions occur in the Northern Hemisphere midlatitudes between winter when all forms of energy transfer matter and summer when only radiation and convection dominate. Seasonality in the Southern Hemisphere midlatitudes was negligible. These results applied to both observations and state-of-the-art climate models. Idealized aquaplanet simulations were used to understand the differences in energy transfer as a function of latitude, hemisphere and season. The idealized simulations show that when the dominant balance is between radiation and convection in aquaplanet simulations without land, the temperature profile is close to what we would expect under adjustment by moist convection. Furthermore, polar sea ice is critical for the dominant balance over the poles between radiation and advection, which leads to a stable stratification of the temperature profile in that region. Idealized simulations with varying surface heat capacity showed that the seasonal transition in the Northern Hemisphere midlatitudes is the result of a lower surface heat capacity (land and ocean) versus a muted seasonality in the Southern Hemisphere due to a larger heat capacity through ocean energy storage.
The results further showed that the energy transfer regimes in the present climate can be used to interpret the response to warming. In particular, regions where radiation and convection dominate are associated with a warming response that is largest in the upper troposphere. Whereas regions where radiation and advection dominate are associated with a warming response that is largest at the surface. In addition, in the Arctic there is an energy transfer regime transition that is associated with Arctic Sea ice loss. The transition involves an increase in convective precipitation in the Arctic. A transient regime transition was also noted over the Southern Ocean, driven in large parts by strong ocean heat uptake. However this transition was only found for much larger changes in carbon dioxide concentration that will likely not be reached in the future.
The broader impact outcomes of this project include the training of two graduate students in atmospheric and climate dynamics and one undergraduate student.
Last Modified: 05/17/2024
Modified by: Tiffany A Shaw
Please report errors in award information by writing to: awardsearch@nsf.gov.
