The MAT1NXLND or tavg1_2d_lnd_Nx data product is the MERRA Data Assimilation System 2-Dimensional land surface diagnostic that is time averaged single-level at the native resolution. It is a history file that is produced from the GCM during the corrector segment of the IAU cycle. All collections from this group are at reduced horizontal resolution. MERRA, or the Modern Era Retrospective-analysis for Research and Application, is a NASA reanalysis for the satellite era (30 years 1979-current) using the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5 DAS).
                                    
                                    This data product contains 2-dimensional fields that do not vary during the reanalysis. Parameters include:
                                    
                              GRN  - Vegetation greenness fraction 
                              LAI  - Leaf area index 
                              GWETROOT - Root zone soil wetness 
                              GWETTOP  - Top soil layer wetness 
                              TPSNOW  - Top snow layer temperature 
                              TUNST  - Surface temperature of unsaturated zone 
                              TSAT  - Surface temperature of saturated zone 
                              TWLT  - Surface temperature of wilted zone 
                              PRECSNO  - Surface snowfall
                              PRECTOT  - Total surface precipitation
                              SNOMAS - Snow mass 
                              SNODP - Snow depth 
                              EVPSOIL  - Bare soil eEvaporation 
                              EVPTRNS  - Transpiration 
                              EVPINTR  - Interception loss 
                              EVPSBLN  - Sublimation 
                              RUNOFF  - Overland runoff 
                              BASEFLOW  - Baseflow 
                              SMLAND  - Snowmelt 
                              FRUNST  - Fractional unsaturated area 
                              FRSAT  - Fractional saturated area 
                              FRSNO  - Fractional snow-covered area 
                              FRWLT  - Fractional wilting area 
                              PARDF  - Surface downward PAR diffuse flux 
                              PARDR  - Surface downward PAR beam flux 
                              SHLAND  - Sensible heat flux from land 
                              LHLAND  - Latent heat flux from land 
                              EVLAND  - Evaporation from land 
                              LWLAND  - Net downward longwave flux over land 
                              SWLAND  - Net downward shortwave flux over land 
                              GHLAND  - Downward heat flux at base of top soil layer 
                              TWLAND  - Total water store in land reservoirs 
                              TELAND  - Energy store in all land reservoirs 
                              WCHANGE  - Total land water change per unit time 
                              ECHANGE  - Total land energy change per unit time
                              
                                    The data are on the GEOS-5 native 540 x 361 grid with 2/3&amp;deg; longitude x 1/2&amp;deg; latitude resolution. Data are archived in the HDF-EOS (Grid) format, based on HDF4.