| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
|
| Initial Amendment Date: | March 23, 2011 |
| Latest Amendment Date: | April 14, 2013 |
| Award Number: | 1062206 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Eric DeWeaver
edeweave@nsf.gov (703)292-8527 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | May 1, 2011 |
| End Date: | April 30, 2016 (Estimated) |
| Total Intended Award Amount: | $320,721.00 |
| Total Awarded Amount to Date: | $320,721.00 |
| Funds Obligated to Date: |
FY 2012 = $101,992.00 FY 2013 = $104,667.00 |
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
615 W 131ST ST NEW YORK NY US 10027-7922 (212)854-6851 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
615 W 131ST ST NEW YORK NY US 10027-7922 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Climate & Large-Scale Dynamics |
| Primary Program Source: |
01001213DB NSF RESEARCH & RELATED ACTIVIT 01001314DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
This project will conduct a series of experiments with a hierarchy of numerical models to improve understanding of the Madden-Julian Oscillation (MJO), a large-scale weather pattern that forms in the Indian Ocean and propagates slowly eastward into the central equatorial Pacific. The project is one component of the DYNAmics of the Madden-julian Oscillation (DYNAMO) field campaign, in which observations will be collected in the Indian Ocean from ships, islands, and aircraft between October 2011 and March 2012. The field campaign is a multi-agency effort with funding from NSF, the National Oceanic and Atmospheric Administration, the Department of Energy, and the Office of Naval Research, with international partiners including India, Japan, the Maldives, France, and several other countries.
The specific goals of this project are to test DYNAMO hypotheses on the roles of moistening processes and specific convective populations in MJO initiation, evaluate model performance, and provide feedback for model development. Specific tasks of the project are 1) to analyze the DYNAMO observations, both to test the DYNAMO hypotheses directly and to provide context and targets for further modeling efforts; 2) to perform and analyze hindcast experiments with global models that explicitly represent moist convection to augment DYNAMO observations in constraining the large-scale budgets and testing the roles of various processes in MJO initiation; 3) To compare observations with results from cloud-system-resolving models (CSRM) on limited domains, both forced in the traditional way using tendencies derived from the DYNAMO sounding array and in a more theoretical mode with forcing parameterized interactively; 4) to compare results from the limited domain CSRMs and single column models with convective parameterizations using the same forcing methods; and 5) To use results from the previous steps to improve and test a cumulus parameterization in a version of the NCAR global climate model. Specific DYNAMO observations to be used in the project include the temperature, moisture, and advective tendency profiles from the radiosonde network, radar observations, and an integrated surface flux dataset funded by the Office of Naval Research.
Motivation for this project and more generally for DYNAMO comes from the many ways in which the MJO affects weather and climate worldwide. The MJO regulates the active and break periods of the Asian and Australian monsoon systems, serves as a forcing agent for El Nino events, and, when it propagates into the Pacific ocean, impacts weather over the United States. MJO activity over the Pacific Ocean has a strong influence on hurricane formation in the Gulf of Mexico. Improved prediction of the MJO could thus allow long-lead forecasts (up to two weeks) of its worldwide weather and climate impacts, and research conducted under this project could serve as the basis for such advances in MJO prediction. In addition, this project will provide support and training to three graduate students and a postdoctoral fellow, thereby promoting the next generation of scientists in tropical meteorology and climatology. The project will also support a range of outreach activities including recruitment of minority students to graduate education in a STEM discipline, presentations in K-8 schools, and DYNAMO and MJO-themed activities at institution-wide outreach events at the supported institutions.
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 Madden-Julian oscillation (MJO) is a disturbance in the tropical atmosphere in between weather and climate. The MJO evolves over periods of weeks, typically completing a cycle in a month or two. Although the MJO is strongest in the equatorial Indian and western Pacific oceans, it causes changes in weather over large portions of the globe. Because the MJO is somewhat predictable, our knowledge of it creates the possibility for forecasts on time scales of 2-4 weeks.
While weather and climate models have become better at simulating and predicting the MJO, making such forecasts a reality, scientists still do not fully understand the basic mechanics which cause the MJO to occur. This lack of understanding ultimately limits both our ability to forecast individual MJO events, and our ability to make projections of how the MJO overall will change as the climate warms due to increasing greenhouse gas concentrations. The goal of our project was to improve our fundamental understanding of the mechanisms of the MJO. Why does the MJO exist? Why do its large-scale weather disturbances move slowly eastward? Why do those disturbances have the structure and other properties that they have?
The specific focus of the project was a field campaign conducted called Dynamics of the Madden Julian Oscillation (DYNAMO), conducted in late 2011 in the equatorial Indian ocean in and around the Maldives. Our project combined analysis of some of the observations gathered in this campaign with numerical model simulations. The numerical model simulations provide an experimental capability. Once a simulation adequately captures MJO events which occurred in reality, we can change things about the model and see how much difference they make to the results. This allows us to determine which factors are most important to the observed behavior.
Much of the difficulty in understanding the MJO stems from the complexity of the interactions between clouds, which are relatively small, and the atmospheric circulations associated with entire MJO events, which are much larger. Our project demonstrated the ability of a new simulation method to capture the MJO while allowing us to deconstruct the complex interactions between the clouds and the large-scale circulations. This simulation method involves what are known as "parameterizations of large-scale dynamics". Though it had been used to study other phenomena, this was the first application to the MJO (and one of the first applications to any specific sequence of weather observations, as opposed to broader patterns based on the statistics of larger sets of observations).
We use a model which simulates clouds in a small region - much smaller than the MJO event itself - allowing us to use high resolution, like many pixels in a digital camera image, to simulate the clouds relatively well. We then represent the interaction with the larger scale circulations in a simplified way, without actually simulating those circulations explicitly, based on our broader understanding of how those large-scale circulations work. We demonstrated that this method works to simulate the MJO events that occurred during DYNAMO, and then used this method to deconstruct the key mechanisms by changing various aspects of the model and simulation method.
The results are consistent with an emerging view that the MJO is a “moisture mode”, a type of atmospheric disturbance which owes its existence, or at least many of its most important properties, to the fact that the atmosphere contains water vapor. More specifically, our results indicate that the way clouds modify the atmosphere’s absorption and emission of infrared radiation is important to the existence and strength of MJO events. They also are consistent with the idea that the MJO moves towards the east because of the way the circulation transports moisture, moistening the region to the east of the MJO disturbances and drying the region to the west. Our analysis of the DYNAMO observations also support this view, as do simulations we performed with more conventional methods, including those using a larger domain (at lower resolution) in which we explicitly captured the large-scale circulations.
The net results of our project are to further strengthen the evidence base for the moisture mode theory of the MJO, and to develop a new simulation method which can now be used to study other tropical weather and climate phenomena as well.
Last Modified: 08/03/2016
Modified by: Adam H Sobel
Please report errors in award information by writing to: awardsearch@nsf.gov.
