ERA5.1: Corrections to ERA5 Stratospheric Temperature 2000-2006

• Main Author: European Centre For Medium-Range Weather Forecasts
• Format: Dataset
• Language: English
• Published: UCAR/NCAR - Research Data Archive 2020
• Subjects: EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW/ICE TEMPERATURE; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER > SURFACE WATER PROCESSES/MEASUREMENTS > RUNOFF; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW MELT; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW DENSITY; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW DEPTH; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > ALBEDO; EARTH SCIENCE > OCEANS > SEA ICE > ICE EXTENT; EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > SEA SURFACE TEMPERATURE; EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > SURFACE ROUGHNESS; EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION; EARTH SCIENCE > LAND SURFACE > SURFACE THERMAL PROPERTIES > SKIN TEMPERATURE; EARTH SCIENCE > LAND SURFACE > SURFACE RADIATIVE PROPERTIES > ALBEDO; EARTH SCIENCE > LAND SURFACE > SOILS > SOIL TEMPERATURE; EARTH SCIENCE > LAND SURFACE > SOILS > SOIL MOISTURE/WATER CONTENT; EARTH SCIENCE > LAND SURFACE > SOILS > SOIL CLASSIFICATION; EARTH SCIENCE > CRYOSPHERE > SNOW/ICE > SNOW/ICE TEMPERATURE; EARTH SCIENCE > BIOSPHERE > VEGETATION > VEGETATION SPECIES; EARTH SCIENCE > BIOSPHERE > VEGETATION > VEGETATION COVER; EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > SOLID PRECIPITATION > SNOW; EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > PRECIPITATION AMOUNT; EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD FREQUENCY; EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD MICROPHYSICS > CLOUD LIQUID WATER/ICE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > WIND STRESS; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > VORTICITY; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > VERTICAL WIND VELOCITY/SPEED; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > CONVERGENCE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > CONVECTION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > UPPER LEVEL WINDS; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > SURFACE WINDS; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR PROCESSES > EVAPORATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > WATER VAPOR; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > TOTAL PRECIPITABLE WATER; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > HUMIDITY; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > DEW POINT TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > UPPER AIR TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > MAXIMUM/MINIMUM TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > AIR TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > SHORTWAVE RADIATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > OUTGOING LONGWAVE RADIATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > LONGWAVE RADIATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > INCOMING SOLAR RADIATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > HEAT FLUX; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > SURFACE PRESSURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > SEA LEVEL PRESSURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > GRAVITY WAVE; EARTH SCIENCE > ATMOSPHERE > ALTITUDE > PLANETARY BOUNDARY LAYER HEIGHT; EARTH SCIENCE > ATMOSPHERE > ALTITUDE > GEOPOTENTIAL HEIGHT; EARTH SCIENCE > ATMOSPHERE > AIR QUALITY > TROPOSPHERIC OZONE; South Pole; Sea ice; South pole
• Online Access: https://dx.doi.org/10.5065/cbtn-v814; https://rda.ucar.edu/datasets/ds633.2/

In ECMWF Technical Memo 859 released in January 2020, Simmons and his coauthors report that "the ERA5 analyses of lower stratospheric temperature exhibit a pronounced cold bias for the years 2000 to 2006. This is due to specifying background error covariances for the data assimilation that were inappropriate prior to availability during 2006 of GNSS radio occultation data in sufficient numbers to constrain a cold bias of the assimilating ERA5 model. A new set of analyses, termed ERA5.1, has thus been produced for the period from 2000 to 2006 using the background error covariances that were used to produce the ERA5 analyses for the years 1979 to 1999. ERA5.1 also includes the more restrictive ensemble assimilation of SBUV ozone data that was used in production of ERA5 for 1979 to 1999.""ERA5.1 provides analyses with better global-mean temperatures in the stratosphere and uppermost troposphere than provided by ERA5. ERA5.1 stands up well in comparison with ERA-Interim and other reanalyses in the lower stratosphere, although there are also lower-stratospheric temperature differences between ERA5 and other reanalyses in the 1980s and 1990s. These are due in part to differences in radiosonde temperature bias adjustment. The pronounced near-tropopause cold bias of ERA5 from 2000 to 2006 has implications for the representation of stratospheric humidity, for which ERA5.1 performs better, though by no means perfectly. ERA5.1 does not exhibit the spuriously high values of ozone that occur close to the South Pole in the polar nights of 2003 and 2004 in the ERA5 analyses. Synoptic evolution in the extratropical stratosphere is seen to be very similar in two cases involving splitting of the stratospheric polar vortex and secondary vortex formation by dynamical instability. The ERA5.1 representation of the QBO agrees slightly better with radiosonde wind data than that of ERA5. The dataset formed by merging ERA5.1 with ERA5 is generally more homogeneous over time than ERA5 alone. It nevertheless is problematic for global-mean upper stratospheric temperature for all but the most recent ten or so years.""ERA5.1 is very close to ERA5 in the lower and middle troposphere."