Abstract
Many theories for the Madden-Julian oscillation (MJO) focus on diabatic processes, particularly the evolution of vertical heating and moistening. Poor MJO performance in weather and climate models is often blamed on biases in these processes and their interactions with the large-scale circulation. We introduce one of the three components of a model evaluation project, which aims to connect MJO fidelity in models to their representations of several physical processes, focusing on diabatic heating and moistening. This component consists of 20day hindcasts, initialized daily during two MJO events in winter 2009-2010. The 13 models exhibit a range of skill: several have accurate forecasts to 20days lead, while others perform similarly to statistical models (8-11days). Models that maintain the observed MJO amplitude accurately predict propagation, but not vice versa. We find no link between hindcast fidelity and the precipitation-moisture relationship, in contrast to other recent studies. There is also no relationship between models' performance and the evolution of their diabatic heating profiles with rain rate. A more robust association emerges between models' fidelity and net moistening: the highest-skill models show a clear transition from low-level moistening for light rainfall to midlevel moistening at moderate rainfall and upper level moistening for heavy rainfall. The midlevel moistening, arising from both dynamics and physics, may be most important. Accurately representing many processes may be necessary but not sufficient for capturing the MJO, which suggests that models fail to predict the MJO for a broad range of reasons and limits the possibility of finding a panacea.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4690-4717 |
| Number of pages | 28 |
| Journal | Journal of Geophysical Research C: Oceans |
| Volume | 120 |
| Issue number | 10 |
| DOIs | |
| State | Published - May 27 2015 |
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Keywords
- diabatic heating
- diabatic moistening
- hindcasts
- Madden-Julian oscillation
- model evaluation
- tropical convection
ASJC Scopus subject areas
- Atmospheric Science
- Geophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
Cite this
Vertical structure and physical processes of the Madden-Julian oscillation : Linking hindcast fidelity to simulated diabatic heating and moistening. / Klingaman, Nicholas P.; Woolnough, Steven J.; Jiang, Xianan; Waliser, Duane; Xavier, Prince K.; Petch, Jon; Caian, Mihaela; Hannay, Cecile; Kim, Daehyun; Ma, Hsi Yen; Merryfield, William J.; Miyakawa, Tomoki; Pritchard, Mike; Ridout, James A.; Roehrig, Romain; Shindo, Eiki; Vitart, Frederic; Wang, Hailan; Cavanaugh, Nicholas R.; Mapes, Brian E; Shelly, Ann; Zhang, Guang J.
In: Journal of Geophysical Research C: Oceans, Vol. 120, No. 10, 27.05.2015, p. 4690-4717.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Vertical structure and physical processes of the Madden-Julian oscillation
T2 - Linking hindcast fidelity to simulated diabatic heating and moistening
AU - Klingaman, Nicholas P.
AU - Woolnough, Steven J.
AU - Jiang, Xianan
AU - Waliser, Duane
AU - Xavier, Prince K.
AU - Petch, Jon
AU - Caian, Mihaela
AU - Hannay, Cecile
AU - Kim, Daehyun
AU - Ma, Hsi Yen
AU - Merryfield, William J.
AU - Miyakawa, Tomoki
AU - Pritchard, Mike
AU - Ridout, James A.
AU - Roehrig, Romain
AU - Shindo, Eiki
AU - Vitart, Frederic
AU - Wang, Hailan
AU - Cavanaugh, Nicholas R.
AU - Mapes, Brian E
AU - Shelly, Ann
AU - Zhang, Guang J.
PY - 2015/5/27
Y1 - 2015/5/27
N2 - Many theories for the Madden-Julian oscillation (MJO) focus on diabatic processes, particularly the evolution of vertical heating and moistening. Poor MJO performance in weather and climate models is often blamed on biases in these processes and their interactions with the large-scale circulation. We introduce one of the three components of a model evaluation project, which aims to connect MJO fidelity in models to their representations of several physical processes, focusing on diabatic heating and moistening. This component consists of 20day hindcasts, initialized daily during two MJO events in winter 2009-2010. The 13 models exhibit a range of skill: several have accurate forecasts to 20days lead, while others perform similarly to statistical models (8-11days). Models that maintain the observed MJO amplitude accurately predict propagation, but not vice versa. We find no link between hindcast fidelity and the precipitation-moisture relationship, in contrast to other recent studies. There is also no relationship between models' performance and the evolution of their diabatic heating profiles with rain rate. A more robust association emerges between models' fidelity and net moistening: the highest-skill models show a clear transition from low-level moistening for light rainfall to midlevel moistening at moderate rainfall and upper level moistening for heavy rainfall. The midlevel moistening, arising from both dynamics and physics, may be most important. Accurately representing many processes may be necessary but not sufficient for capturing the MJO, which suggests that models fail to predict the MJO for a broad range of reasons and limits the possibility of finding a panacea.
AB - Many theories for the Madden-Julian oscillation (MJO) focus on diabatic processes, particularly the evolution of vertical heating and moistening. Poor MJO performance in weather and climate models is often blamed on biases in these processes and their interactions with the large-scale circulation. We introduce one of the three components of a model evaluation project, which aims to connect MJO fidelity in models to their representations of several physical processes, focusing on diabatic heating and moistening. This component consists of 20day hindcasts, initialized daily during two MJO events in winter 2009-2010. The 13 models exhibit a range of skill: several have accurate forecasts to 20days lead, while others perform similarly to statistical models (8-11days). Models that maintain the observed MJO amplitude accurately predict propagation, but not vice versa. We find no link between hindcast fidelity and the precipitation-moisture relationship, in contrast to other recent studies. There is also no relationship between models' performance and the evolution of their diabatic heating profiles with rain rate. A more robust association emerges between models' fidelity and net moistening: the highest-skill models show a clear transition from low-level moistening for light rainfall to midlevel moistening at moderate rainfall and upper level moistening for heavy rainfall. The midlevel moistening, arising from both dynamics and physics, may be most important. Accurately representing many processes may be necessary but not sufficient for capturing the MJO, which suggests that models fail to predict the MJO for a broad range of reasons and limits the possibility of finding a panacea.
KW - diabatic heating
KW - diabatic moistening
KW - hindcasts
KW - Madden-Julian oscillation
KW - model evaluation
KW - tropical convection
UR - http://www.scopus.com/inward/record.url?scp=84932199392&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84932199392&partnerID=8YFLogxK
U2 - 10.1002/2014JD022374
DO - 10.1002/2014JD022374
M3 - Article
AN - SCOPUS:84932199392
VL - 120
SP - 4690
EP - 4717
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
SN - 2169-9275
IS - 10
ER -