The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2).

The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) is the latest atmospheric reanalysis of the modern satellite era produced by NASA's Global Modeling and Assimilation Office (GMAO). MERRA-2 assimilates observation types not available to its predecessor, MERRA, and includes updates to the Goddard Earth Observing System (GEOS) model and analysis scheme so as to provide a viable ongoing climate analysis beyond MERRA's terminus. While addressing known limitations of MERRA, MERRA-2 is also intended to be a development milestone for a future integrated Earth system analysis (IESA) currently under development at GMAO. This paper provides an overview of the MERRA-2 system and various performance metrics. Among the advances in MERRA-2 relevant to IESA are the assimilation of aerosol observations, several improvements to the representation of the stratosphere including ozone, and improved representations of cryospheric processes. Other improvements in the quality of MERRA-2 compared with MERRA include the reduction of some spurious trends and jumps related to changes in the observing system, and reduced biases and imbalances in aspects of the water cycle. Remaining deficiencies are also identified. Production of MERRA-2 began in June 2014 in four processing streams, and converged to a single near-real time stream in mid 2015. MERRA-2 products are accessible online through the NASA Goddard Earth Sciences Data Information Services Center (GES DISC).

[1]  B. Marticorena,et al.  Modeling the atmospheric dust cycle: 1. Design of a soil-derived dust emission scheme , 1995 .

[2]  F. Joseph Turk,et al.  An 11-year global gridded aerosol optical thickness reanalysis (v1.0) for atmospheric and climate sciences , 2016 .

[3]  Kathleen A. Crean,et al.  Multiangle imaging spectroradiometer (MISR) global aerosol optical depth validation based on 2 years of coincident Aerosol Robotic Network (AERONET) observations : Global aerosol system , 2005 .

[4]  Ronald M. Errico,et al.  Improving Incremental Balance in the GSI 3DVAR Analysis System , 2009 .

[5]  P. Jones,et al.  The Twentieth Century Reanalysis Project , 2009 .

[6]  John Turner,et al.  The SCAR READER Project: toward a high-quality database of mean Antarctic meteorological observations , 2004 .

[7]  D. Dee,et al.  Variational bias correction of satellite radiance data in the ERA‐Interim reanalysis , 2009 .

[8]  Fuzhong Weng,et al.  JCSDA Community Radiative Transfer Model (CRTM) : version 1 , 2006 .

[9]  S. Hoch.  Radiative flux divergence in the surface boundary layer: A study based on observations at Summit, Greenland , 2005 .

[10]  D. Dee,et al.  Toward a consistent reanalysis of the upper stratosphere based on radiance measurements from SSU and AMSU‐A , 2009 .

[11]  J. Farman,et al.  Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interaction , 1985, Nature.

[12]  Thomas M. Smith,et al.  An Improved In Situ and Satellite SST Analysis for Climate , 2002 .

[13]  Angela Benedetti,et al.  The CAMS interim Reanalysis of Carbon Monoxide, Ozone and Aerosol for 2003–2015 , 2016 .

[14]  Michael G. Bosilovich,et al.  Global Energy and Water Budgets in MERRA , 2011 .

[15]  Gary B. Brassington,et al.  Progress and challenges in short- to medium-range coupled prediction , 2015 .

[16]  J. Thepaut,et al.  A reassessment of temperature variations and trends from global reanalyses and monthly surface climatological datasets , 2017 .

[17]  Thomas M. Smith,et al.  Daily High-Resolution-Blended Analyses for Sea Surface Temperature , 2007 .

[18]  M. Chin,et al.  A review of measurement-based assessments of the aerosol direct radiative effect and forcing , 2005 .

[19]  Kevin E. Trenberth,et al.  The Mass of the Atmosphere: A Constraint on Global Analyses , 2005 .

[20]  Max J. Suarez,et al.  The Impact of Detailed Snow Physics on the Simulation of Snow Cover and Subsurface Thermodynamics at Continental Scales , 2001 .

[21]  John Derber,et al.  The National Meteorological Center's spectral-statistical interpolation analysis system , 1992 .

[22]  J. Ziemke,et al.  The global structure of upper troposphere‐lower stratosphere ozone in GEOS‐5: A multiyear assimilation of EOS Aura data , 2015 .

[23]  Lars Isaksen,et al.  Use and impact of automated aircraft data in a global 4DVAR data assimilation system , 2003 .

[24]  Michael F. Wehner,et al.  Monitoring and Understanding Trends in Extreme Storms: State of Knowledge , 2013 .

[25]  S. Moorthi,et al.  Relaxed Arakawa-Schubert - A parameterization of moist convection for general circulation models , 1992 .

[26]  C. Frantzidis,et al.  Response to Reviewers Reviewer #1 , 2010 .

[27]  Lawrence L. Takacs,et al.  Data Assimilation Using Incremental Analysis Updates , 1996 .

[28]  R. Koster,et al.  Assessment and Enhancement of MERRA Land Surface Hydrology Estimates , 2011 .

[29]  J. Janowiak,et al.  The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present) , 2003 .

[30]  Paul Poli,et al.  Estimating low‐frequency variability and trends in atmospheric temperature using ERA‐Interim , 2014 .

[31]  Krzysztof Wargan,et al.  Strengthening of the Tropopause Inversion Layer during the 2009 Sudden Stratospheric Warming: A MERRA-2 Study , 2016 .

[32]  Peter J. Minnett,et al.  Sea Surface Temperature , 2001 .

[33]  S. Gong,et al.  A parameterization of sea‐salt aerosol source function for sub‐ and super‐micron particles , 2003 .

[34]  Shian-Jiann Lin,et al.  Finite-volume transport on various cubed-sphere grids , 2007, J. Comput. Phys..

[35]  E. Vermote,et al.  Second‐generation operational algorithm: Retrieval of aerosol properties over land from inversion of Moderate Resolution Imaging Spectroradiometer spectral reflectance , 2007 .

[36]  Dick Dee,et al.  On the choice of variable for atmospheric moisture analysis , 2022 .

[37]  P. Newman,et al.  The Unusual Southern Hemisphere Stratosphere Winter of 2002 , 2005 .

[38]  W. Greuell,et al.  Numerical modelling of the energy balance and the englacial temperature of the Greenland Ice Sheet. Calculations for the ETH-Camp location (West Greenland, 1155 m a.s.l.) , 1994 .

[39]  Lance E. Christensen,et al.  Early validation analyses of atmospheric profiles from EOS MLS on the aura Satellite , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[40]  W. Collins,et al.  An AeroCom Initial Assessment - Optical Properties in Aerosol Component Modules of Global Models , 2005 .

[41]  Richard B. Rood,et al.  An assimilated dataset for Earth science applications , 1993 .

[42]  J. Box,et al.  Evaluation of Greenland Ice Sheet Surface Climate in the HIRHAM Regional Climate Model Using Automatic Weather Station Data , 2003 .

[43]  P. Chyacutelek,et al.  Aerosols and climate. , 1974 .

[44]  C. Kobayashi,et al.  The JRA-55 Reanalysis: General Specifications and Basic Characteristics , 2015 .

[45]  M. Bosilovich.  Regional Climate and Variability of NASA MERRA and Recent Reanalyses: U.S. Summertime Precipitation and Temperature , 2013 .

[46]  John Derber,et al.  The Use of TOVS Cloud-Cleared Radiances in the NCEP SSI Analysis System , 1998 .

[47]  E. Holm,et al.  Revision of the ECMWF humidity analysis: Construction of a gaussian control variable , 2003 .

[48]  Rolf H. Reichle,et al.  Observation-Corrected Precipitation Estimates in GEOS-5 , 2014 .

[49]  Peter Bauer,et al.  Direct 4D‐Var assimilation of all‐sky radiances. Part I: Implementation , 2010 .

[50]  G. Stephens,et al.  Spatial statistics of likely convective clouds in CloudSat data , 2010 .

[51]  V. Kumar,et al.  Systematic Differences in Aircraft and Radiosonde Temperatures , 2008 .

[52]  Paul Poli,et al.  Atmospheric conservation properties in ERA‐Interim , 2011 .

[53]  P. Xie,et al.  A Gauge-Based Analysis of Daily Precipitation over East Asia , 2007 .

[54]  Ricardo Todling,et al.  Assimilation for skin SST in the NASA GEOS atmospheric data assimilation system , 2017, Quarterly journal of the Royal Meteorological Society. Royal Meteorological Society.

[55]  R. Koster,et al.  Land Surface Precipitation in MERRA-2 , 2017 .

[56]  Johannes Quaas,et al.  Estimates of aerosol radiative forcing from the MACC re-analysis , 2012 .

[57]  M. Bosilovich,et al.  Evaluation of the Reanalysis Products from GSFC, NCEP, and ECMWF Using Flux Tower Observations , 2012 .

[58]  M. Miller,et al.  The Seasonal Cycle of the Radiation Budget and Cloud Radiative Effect in the Amazon Rain Forest of Brazil , 2015 .

[59]  Marc Lynch-Stieglitz,et al.  The development and validation of a simple snow model for the GISS GCM , 1994 .

[60]  Dian J. Seidel,et al.  Stratospheric temperature changes during the satellite era , 2016 .

[61]  Michael G. Bosilovich,et al.  Atmospheric Water Balance and Variability in the MERRA-2 Reanalysis , 2017 .

[62]  Ricardo Todling,et al.  Maintaining atmospheric mass and water balance in reanalyses , 2016, Quarterly journal of the Royal Meteorological Society. Royal Meteorological Society.

[63]  M. Molina,et al.  Stratospheric sink for chlorofluoromethanes: chlorine atomc-atalysed destruction of ozone , 1974, Nature.

[64]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[65]  M. Chin,et al.  Anthropogenic, biomass burning, and volcanic emissions of black carbon, organic carbon, and SO 2 from 1980 to 2010 for hindcast model experiments , 2012 .

[66]  C. Flynn,et al.  The MERRA-2 Aerosol Reanalysis, 1980 - onward, Part I: System Description and Data Assimilation Evaluation. , 2017, Journal of climate.

[67]  Uang,et al.  The NCEP Climate Forecast System Reanalysis , 2010 .

[68]  Claudio Carnevale,et al.  Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models , 2014 .

[69]  G. Labow,et al.  Evaluation of the Ozone Fields in NASA's MERRA-2 Reanalysis. , 2017, Journal of climate.

[70]  J. Pereira,et al.  Global wildland fire emissions from 1960 to 2000 , 2008 .

[71]  James R. Campbell,et al.  Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis , 2014 .

[72]  Richard I. Cullather,et al.  Evaluation of the Surface Representation of the Greenland Ice Sheet in a General Circulation Model , 2014 .

[73]  A. Heidinger,et al.  Using Moderate Resolution Imaging Spectrometer (MODIS) to calibrate advanced very high resolution radiometer reflectance channels , 2002 .

[74]  Michael G. Bosilovich,et al.  The Energy Budget of the Polar Atmosphere in MERRA , 2012 .

[75]  Dong L. Wu,et al.  Title : Validation of the Aura Microwave Limb Sounder Temperature and Geopotential Height Measurements , 2007 .

[76]  Fuzhong Weng,et al.  Validation of the Community Radiative Transfer Model by using CloudSat data , 2008 .

[77]  Gunnar Myhre,et al.  Consistency Between Satellite-Derived and Modeled Estimates of the Direct Aerosol Effect , 2009, Science.

[78]  G. Gayno,et al.  The Land Surface Analysis in the NCEP Climate Forecast System Reanalysis , 2012 .

[79]  J. Holton,et al.  Chapter 12 – Middle Atmosphere Dynamics , 2013 .

[80]  X. Fettweis.  Reconstruction of the 1979–2006 Greenland ice sheet surface mass balance using the regional climate model MAR , 2007 .

[81]  Steven Pawson,et al.  Structure and Dynamics of the Quasi-Biennial Oscillation in MERRA-2. , 2016, Journal of climate.

[82]  M. Bosilovich,et al.  The Effect of Satellite Observing System Changes on MERRA Water and Energy Fluxes , 2011 .

[83]  David D. Parrish,et al.  NORTH AMERICAN REGIONAL REANALYSIS , 2006 .

[84]  R. Koster,et al.  The Quick Fire Emissions Dataset (QFED): Documentation of Versions 2.1, 2.2 and 2.4. Volume 38; Technical Report Series on Global Modeling and Data Assimilation , 2015 .

[85]  E. Vermote,et al.  The MODIS Aerosol Algorithm, Products, and Validation , 2005 .

[86]  S. Schubert,et al.  MERRA: NASA’s Modern-Era Retrospective Analysis for Research and Applications , 2011 .

[87]  R. Koster,et al.  Hydroclimatic Controls on the Means and Variability of Vegetation Phenology and Carbon Uptake , 2014 .

[88]  Quanhua Liu,et al.  Community Radiative Transfer Model (CRTM) applications in supporting the Suomi National Polar-orbiting Partnership (SNPP) mission validation and verification , 2014 .

[89]  J. Derber,et al.  Introduction of the GSI into the NCEP Global Data Assimilation System , 2009 .

[90]  J. Randerson,et al.  Interannual variability in global biomass burning emissions from 1997 to 2004 , 2006 .

[91]  R. Koster,et al.  Large Scale Influences on Summertime Extreme Precipitation in the Northeastern United States. , 2016, Journal of hydrometeorology.

[92]  S. Pawson,et al.  The 2015/16 El Niño Event in Context of the MERRA-2 Reanalysis: A Comparison of the Tropical Pacific with 1982/83 and 1997/98 , 2017 .

[93]  A. Smirnov,et al.  AERONET-a federated instrument network and data archive for aerosol Characterization , 1998 .

[94]  M. Chin,et al.  Online simulations of global aerosol distributions in the NASA GEOS‐4 model and comparisons to satellite and ground‐based aerosol optical depth , 2010 .

[95]  Teruyuki Nakajima,et al.  Tropospheric aerosol optical thickness from the GOCART model and comparisons with satellite and sun photometer measurements , 2002 .

[96]  James M. Russell,et al.  The evolution of the stratopause during the 2006 major warming: Satellite data and assimilated meteorological analyses , 2008 .

[97]  Jean-Noël Thépaut,et al.  The MACC reanalysis: an 8 yr data set of atmospheric composition , 2012 .

[98]  Yoo-Geun Ham,et al.  An assessment of the ENSO forecast skill of GEOS-5 system , 2014, Climate Dynamics.

[99]  C. Donlon,et al.  The Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) system , 2012 .

[100]  Dennis C. Reuter,et al.  An accurate radiative transfer model for use in the direct physical inversion of HIRS2 and MSU Temperature Sounding Data , 1983 .

[101]  Dimitris Balis,et al.  Validation of the Aura Ozone Monitoring Instrument total column ozone product , 2008 .

[102]  P. Duynkerke,et al.  Surface Energy Balance and Turbulence Characteristics Observed at the SHEBA Ice Camp During FIRE III , 2001 .

[103]  Randal D. Koster,et al.  Assessment of MERRA-2 Land Surface Hydrology Estimates , 2017 .

[104]  R. Purser,et al.  Three-Dimensional Variational Analysis with Spatially Inhomogeneous Covariances , 2002 .