TY - JOUR
T1 - Transient eddies in the TES/MCS Ensemble Mars Atmosphere Reanalysis System (EMARS)
AU - Greybush, Steven J.
AU - Gillespie, Hartzel E.
AU - Wilson, R. John
N1 - Funding Information:
We are most grateful for the scientific contributions toward the development of EMARS by Eugenia Kalnay, Ross Hoffman, Thomas Nehrkorn, Mark Leidner, Yongjing Zhao, Matthew Wespetal and others. We thank the MCS team, including Dan McCleese, David Kass, and Armin Kleinböhl, for insights on using the MCS observations for data assimilation; and Luca Montabone for active discussions on comparing EMARS and MACDA. The UK MACDA control simulation, created by Luca Montabone, Stephen Lewis, Peter Read, and collaborators, was provided directly to the authors by Luca Montabone. To request access to the control simulation, contact the MACDA team at lmontabone@SpaceScience.org. We thank two reviewers, Michael Battalio and Jeff Barnes, for very insightful feedback that helped improve this paper. This research made use of computational resources provided by the Penn State Department of CyberScience. This research was funded by NASA MDAP grants NNX11AL25G , NNX14AM13G and 80NSSC17K0690 .
Publisher Copyright:
© 2018
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Transient eddies are important features of Mars atmosphere weather, and are linked to the genesis of dust storms. Many previous studies of transient eddies, also known as traveling waves, generally used either spacecraft observations or model simulations alone. Reanalyses, which optimally combine observations with a forecast model, provide an unprecedented opportunity to examine these traveling weather systems: their temperature, wind, pressure signatures and structure; the evolution between various wave regimes; and their seasonality and interannual variability. Using the GFDL Mars Global Climate Model (MGCM) with the Local Ensemble Transform Kalman Filter (LETKF), we have created a six year reanalysis of both Thermal Emission Spectrometer (TES) and Mars Climate Sounder (MCS) temperature retrievals, which we name the Ensemble Mars Atmosphere Reanalysis System (EMARS). We demonstrate that the transient eddies in analyses with different assumptions in the model and assimilation system, including between EMARS and the Mars Analysis Correction Data Assimilation reanalysis (MACDA), are generally robust; EMARS and MACDA eddies are more similar to each other than their respective freely running control simulations. We also reveal lower atmosphere transient eddies derived from MCS data for the first time, and compare to those derived from TES data. MCS, as a limb sounder, demonstrates some challenges in constraining the shallow eddies in EMARS compared to reanalyses using TES nadir measurements. Ensemble reanalyses are valuable in that they provide an assessment of convergence upon a unique synoptic state. We examine the six year climatology and interannual variability of transient eddies, synoptic maps, and transitions between dominant wavenumber regimes. Finally, we compare reanalysis products to other products derived from observational data, including radio science and the Viking lander surface pressure records.
AB - Transient eddies are important features of Mars atmosphere weather, and are linked to the genesis of dust storms. Many previous studies of transient eddies, also known as traveling waves, generally used either spacecraft observations or model simulations alone. Reanalyses, which optimally combine observations with a forecast model, provide an unprecedented opportunity to examine these traveling weather systems: their temperature, wind, pressure signatures and structure; the evolution between various wave regimes; and their seasonality and interannual variability. Using the GFDL Mars Global Climate Model (MGCM) with the Local Ensemble Transform Kalman Filter (LETKF), we have created a six year reanalysis of both Thermal Emission Spectrometer (TES) and Mars Climate Sounder (MCS) temperature retrievals, which we name the Ensemble Mars Atmosphere Reanalysis System (EMARS). We demonstrate that the transient eddies in analyses with different assumptions in the model and assimilation system, including between EMARS and the Mars Analysis Correction Data Assimilation reanalysis (MACDA), are generally robust; EMARS and MACDA eddies are more similar to each other than their respective freely running control simulations. We also reveal lower atmosphere transient eddies derived from MCS data for the first time, and compare to those derived from TES data. MCS, as a limb sounder, demonstrates some challenges in constraining the shallow eddies in EMARS compared to reanalyses using TES nadir measurements. Ensemble reanalyses are valuable in that they provide an assessment of convergence upon a unique synoptic state. We examine the six year climatology and interannual variability of transient eddies, synoptic maps, and transitions between dominant wavenumber regimes. Finally, we compare reanalysis products to other products derived from observational data, including radio science and the Viking lander surface pressure records.
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U2 - 10.1016/j.icarus.2018.07.001
DO - 10.1016/j.icarus.2018.07.001
M3 - Article
AN - SCOPUS:85051241589
VL - 317
SP - 158
EP - 181
JO - Icarus
JF - Icarus
SN - 0019-1035
ER -