Adrian Simmons - Academia.edu (original) (raw)
Papers by Adrian Simmons
For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional ... more For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across glo...
Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This public... more Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This publication is not to be reprinted or translated in whole or in part without the written permission of the Director. Appropriate non-commercial use will normally be granted under the condition that reference is made to ECMWF. The information within this publication is given in good faith and considered to be true, but ECMWF accepts no liability for error, omission and for loss or damage arising from its use. ERA-40 Atlas Personal Foreword by Brian Hoskins This atlas is the latest in a sequence that was originally inspired by the diagnostics of the general circulation of the atmosphere produced by Mike Wallace, Maurice Blackmon, Gabriel Lau and collaborators. In the middle and late 1970s they had taken advantage of the availability on magnetic tape of 10 years of routine analyses produced by the US National Meteorological Center for the region 20–90N. The advent and archiving of routine global analyses by the recently established European Centre for Medium-Range Forecasts (ECMWF) in Reading provided the opportunity to diagnose the global circulation. This opportunity was exploited in a Joint Diagnostics project involving the University of Reading, ECMWF and the UK Met Office. The diagnostics of ECMWF data were a crucial part of our activity in the UK Universities Modelling Group. Atlases were produced for the individual years 1980–81, 1981–82 and the
Quarterly Journal of the Royal Meteorological Society, 2021
The extension of the ERA5 reanalysis back to 1950 supplements the previously published segment co... more The extension of the ERA5 reanalysis back to 1950 supplements the previously published segment covering 1979 to the present. It features the assimilation of additional conventional observations, as well as improved use of early satellite data. The number of observations assimilated increases from 53,000 per day in early 1950 to 570,000 per day by the end of 1978. Accordingly, the quality of the reanalysis improves throughout the period, generally joining seamlessly with the segment covering 1979 to the present. The fidelity of the extension is illustrated by the accurate depiction of the North Sea storm of 1953, and the events leading to the first discovery of sudden stratospheric warmings in 1952. Time series of ERA5 global surface temperature anomalies show temperatures to be relatively stable from 1950 until the late 1970s, in agreement with the other contemporary full‐input reanalysis covering this period and with independent data sets, although there are significant differences...
Bulletin of the American Meteorological Society, 2018
Editor’s note: For easy download the posted pdf of the State of the Climate for 2018 is a low-res... more Editor’s note: For easy download the posted pdf of the State of the Climate for 2018 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.
Procedia Environmental Sciences, 2010
NATO Science for Peace and Security Series C: Environmental Security, 2011
A near real-time assimilation and forecast system of aerosols has been developed by integration i... more A near real-time assimilation and forecast system of aerosols has been developed by integration in the ECMWF IFS code within the GEMS project. The GEMS aerosol modeling system is novel as it is the first aerosol model fully coupled to a NWP model with data ...
Atmospheric Chemistry and Physics, 2013
Journal of Climate, 2016
The ECMWF twentieth century reanalysis (ERA-20C; 1900–2010) assimilates surface pressure and mari... more The ECMWF twentieth century reanalysis (ERA-20C; 1900–2010) assimilates surface pressure and marine wind observations. The reanalysis is single-member, and the background errors are spatiotemporally varying, derived from an ensemble. The atmospheric general circulation model uses the same configuration as the control member of the ERA-20CM ensemble, forced by observationally based analyses of sea surface temperature, sea ice cover, atmospheric composition changes, and solar forcing. The resulting climate trend estimations resemble ERA-20CM for temperature and the water cycle. The ERA-20C water cycle features stable precipitation minus evaporation global averages and no spurious jumps or trends. The assimilation of observations adds realism on synoptic time scales as compared to ERA-20CM in regions that are sufficiently well observed. Comparing to nighttime ship observations, ERA-20C air temperatures are 1 K colder. Generally, the synoptic quality of the product and the agreement in ...
Monthly Weather Review, 1991
Bulletin of the American Meteorological Society
The Copernicus Climate Change Service (C3S) provides open and free access to state-of-the-art cli... more The Copernicus Climate Change Service (C3S) provides open and free access to state-of-the-art climate data and tools for use by governments, public authorities, and private entities around the world. It is fully funded by the European Union and implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) together with public and private entities in Europe and elsewhere. With over 120,000 registered users worldwide, C3S has rapidly become an authoritative climate service in Europe and beyond, delivering quality-assured climate data and information based on the latest science. Established in 2014, C3S became fully operational in 2018 with the launch of its Climate Data Store, a powerful cloud-based infrastructure providing access to a vast range of global and regional information, including climate data records derived from observations, the latest ECMWF reanalyses, seasonal forecast data from multiple providers, and a large collection of climate projections. The syst...
Bulletin of the American Meteorological Society
The Copernicus Atmosphere Monitoring Service (CAMS), part of the European Union’s Earth observati... more The Copernicus Atmosphere Monitoring Service (CAMS), part of the European Union’s Earth observation program Copernicus, entered operations in July 2015. Implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) as a truly European effort with over 23,500 direct data users and well over 200 million end users worldwide as of March 2022, CAMS delivers numerous global and regional information products about air quality, inventory-based emissions and observation-based surface fluxes of greenhouse gases and from biomass burning, solar energy, ozone and UV radiation, and climate forcings. Access to CAMS products is open and free of charge via the Atmosphere Data Store. The CAMS global atmospheric composition analyses, forecasts, and reanalyses build on ECMWF’s Integrated Forecasting System (IFS) and exploit over 90 different satellite data streams. The global products are complemented by coherent higher-resolution regional air quality products over Europe derived from m...
Quarterly Journal of the Royal Meteorological Society
Bulletin of the American Meteorological Society, 2011
Atmospheric general circulation changes from March 1979 to February 2022 are examined using the E... more Atmospheric general circulation changes from March 1979 to February 2022 are examined using the ERA5 reanalysis. Maps of linear trends and time series for specific areas are presented. Attention is concentrated on monthly, seasonal and annual means, but shorter-timescale variability is also considered, including extremes. Changes in neartropopause winds are the main focus, but related changes in temperature, wind and other variables throughout the troposphere are discussed. Middle-and upper-tropospheric warming is larger in the subtropics and outer tropics than in the deep tropics, except over the Pacific. This is linked with a strengthening and meridional expansion of the tropical easterlies that has received little previous attention. The change occurs predominantly over the first half of the period. Warming over several mid-latitude and subtropical land areas comes close to matching the large warming of the Arctic, in some seasons at least. Westerly upper-level winds in general weaken over the Arctic in winter but strengthen in northern middle latitudes, contrary to arguments based on circulation changes due solely to amplified Arctic warming. The jet-stream region over the eastern North Atlantic and western Europe shifts southward. Westerlies strengthen in a band stretching south-eastwards from the tropical western Pacific to southern Australia, as well as in the polar-jet-stream region that surrounds Antarctica. Extreme jet-stream winds increase over the North Atlantic. Net kinetic energy also increases, mostly associated with sub-monthly variability along the mid-latitude storm tracks and over the tropical Pacific. Available potential energy changes less. Geopotential height shows a distinct pattern of change in stationary long-wave structures. There are increases in surface pressure over the North Pacific and southern mid-latitudes and decreases over the Arctic Ocean and offshore of Antarctica. Several comparisons are made between ERA5 and the JRA-55 reanalysis and between ERA5 and the observations it assimilated. They show reassuring agreement, but some regional differences require further investigation.
Quarterly Journal of the Royal Meteorological Society, 2014
Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This public... more Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This publication is not to be reprinted or translated in whole or in part without the written permission of the Director. Appropriate non-commercial use will normally be granted under the condition that reference is made to ECMWF. The information within this publication is given in good faith and considered to be true, but ECMWF accepts no liability for error, omission and for loss or damage arising from its use. Estimating low-frequency variability and trends in atmospheric temperature… ERA Report Series No.15-Rev.1
For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional ... more For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across glo...
Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This public... more Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This publication is not to be reprinted or translated in whole or in part without the written permission of the Director. Appropriate non-commercial use will normally be granted under the condition that reference is made to ECMWF. The information within this publication is given in good faith and considered to be true, but ECMWF accepts no liability for error, omission and for loss or damage arising from its use. ERA-40 Atlas Personal Foreword by Brian Hoskins This atlas is the latest in a sequence that was originally inspired by the diagnostics of the general circulation of the atmosphere produced by Mike Wallace, Maurice Blackmon, Gabriel Lau and collaborators. In the middle and late 1970s they had taken advantage of the availability on magnetic tape of 10 years of routine analyses produced by the US National Meteorological Center for the region 20–90N. The advent and archiving of routine global analyses by the recently established European Centre for Medium-Range Forecasts (ECMWF) in Reading provided the opportunity to diagnose the global circulation. This opportunity was exploited in a Joint Diagnostics project involving the University of Reading, ECMWF and the UK Met Office. The diagnostics of ECMWF data were a crucial part of our activity in the UK Universities Modelling Group. Atlases were produced for the individual years 1980–81, 1981–82 and the
Quarterly Journal of the Royal Meteorological Society, 2021
The extension of the ERA5 reanalysis back to 1950 supplements the previously published segment co... more The extension of the ERA5 reanalysis back to 1950 supplements the previously published segment covering 1979 to the present. It features the assimilation of additional conventional observations, as well as improved use of early satellite data. The number of observations assimilated increases from 53,000 per day in early 1950 to 570,000 per day by the end of 1978. Accordingly, the quality of the reanalysis improves throughout the period, generally joining seamlessly with the segment covering 1979 to the present. The fidelity of the extension is illustrated by the accurate depiction of the North Sea storm of 1953, and the events leading to the first discovery of sudden stratospheric warmings in 1952. Time series of ERA5 global surface temperature anomalies show temperatures to be relatively stable from 1950 until the late 1970s, in agreement with the other contemporary full‐input reanalysis covering this period and with independent data sets, although there are significant differences...
Bulletin of the American Meteorological Society, 2018
Editor’s note: For easy download the posted pdf of the State of the Climate for 2018 is a low-res... more Editor’s note: For easy download the posted pdf of the State of the Climate for 2018 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.
Procedia Environmental Sciences, 2010
NATO Science for Peace and Security Series C: Environmental Security, 2011
A near real-time assimilation and forecast system of aerosols has been developed by integration i... more A near real-time assimilation and forecast system of aerosols has been developed by integration in the ECMWF IFS code within the GEMS project. The GEMS aerosol modeling system is novel as it is the first aerosol model fully coupled to a NWP model with data ...
Atmospheric Chemistry and Physics, 2013
Journal of Climate, 2016
The ECMWF twentieth century reanalysis (ERA-20C; 1900–2010) assimilates surface pressure and mari... more The ECMWF twentieth century reanalysis (ERA-20C; 1900–2010) assimilates surface pressure and marine wind observations. The reanalysis is single-member, and the background errors are spatiotemporally varying, derived from an ensemble. The atmospheric general circulation model uses the same configuration as the control member of the ERA-20CM ensemble, forced by observationally based analyses of sea surface temperature, sea ice cover, atmospheric composition changes, and solar forcing. The resulting climate trend estimations resemble ERA-20CM for temperature and the water cycle. The ERA-20C water cycle features stable precipitation minus evaporation global averages and no spurious jumps or trends. The assimilation of observations adds realism on synoptic time scales as compared to ERA-20CM in regions that are sufficiently well observed. Comparing to nighttime ship observations, ERA-20C air temperatures are 1 K colder. Generally, the synoptic quality of the product and the agreement in ...
Monthly Weather Review, 1991
Bulletin of the American Meteorological Society
The Copernicus Climate Change Service (C3S) provides open and free access to state-of-the-art cli... more The Copernicus Climate Change Service (C3S) provides open and free access to state-of-the-art climate data and tools for use by governments, public authorities, and private entities around the world. It is fully funded by the European Union and implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) together with public and private entities in Europe and elsewhere. With over 120,000 registered users worldwide, C3S has rapidly become an authoritative climate service in Europe and beyond, delivering quality-assured climate data and information based on the latest science. Established in 2014, C3S became fully operational in 2018 with the launch of its Climate Data Store, a powerful cloud-based infrastructure providing access to a vast range of global and regional information, including climate data records derived from observations, the latest ECMWF reanalyses, seasonal forecast data from multiple providers, and a large collection of climate projections. The syst...
Bulletin of the American Meteorological Society
The Copernicus Atmosphere Monitoring Service (CAMS), part of the European Union’s Earth observati... more The Copernicus Atmosphere Monitoring Service (CAMS), part of the European Union’s Earth observation program Copernicus, entered operations in July 2015. Implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) as a truly European effort with over 23,500 direct data users and well over 200 million end users worldwide as of March 2022, CAMS delivers numerous global and regional information products about air quality, inventory-based emissions and observation-based surface fluxes of greenhouse gases and from biomass burning, solar energy, ozone and UV radiation, and climate forcings. Access to CAMS products is open and free of charge via the Atmosphere Data Store. The CAMS global atmospheric composition analyses, forecasts, and reanalyses build on ECMWF’s Integrated Forecasting System (IFS) and exploit over 90 different satellite data streams. The global products are complemented by coherent higher-resolution regional air quality products over Europe derived from m...
Quarterly Journal of the Royal Meteorological Society
Bulletin of the American Meteorological Society, 2011
Atmospheric general circulation changes from March 1979 to February 2022 are examined using the E... more Atmospheric general circulation changes from March 1979 to February 2022 are examined using the ERA5 reanalysis. Maps of linear trends and time series for specific areas are presented. Attention is concentrated on monthly, seasonal and annual means, but shorter-timescale variability is also considered, including extremes. Changes in neartropopause winds are the main focus, but related changes in temperature, wind and other variables throughout the troposphere are discussed. Middle-and upper-tropospheric warming is larger in the subtropics and outer tropics than in the deep tropics, except over the Pacific. This is linked with a strengthening and meridional expansion of the tropical easterlies that has received little previous attention. The change occurs predominantly over the first half of the period. Warming over several mid-latitude and subtropical land areas comes close to matching the large warming of the Arctic, in some seasons at least. Westerly upper-level winds in general weaken over the Arctic in winter but strengthen in northern middle latitudes, contrary to arguments based on circulation changes due solely to amplified Arctic warming. The jet-stream region over the eastern North Atlantic and western Europe shifts southward. Westerlies strengthen in a band stretching south-eastwards from the tropical western Pacific to southern Australia, as well as in the polar-jet-stream region that surrounds Antarctica. Extreme jet-stream winds increase over the North Atlantic. Net kinetic energy also increases, mostly associated with sub-monthly variability along the mid-latitude storm tracks and over the tropical Pacific. Available potential energy changes less. Geopotential height shows a distinct pattern of change in stationary long-wave structures. There are increases in surface pressure over the North Pacific and southern mid-latitudes and decreases over the Arctic Ocean and offshore of Antarctica. Several comparisons are made between ERA5 and the JRA-55 reanalysis and between ERA5 and the observations it assimilated. They show reassuring agreement, but some regional differences require further investigation.
Quarterly Journal of the Royal Meteorological Society, 2014
Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This public... more Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This publication is not to be reprinted or translated in whole or in part without the written permission of the Director. Appropriate non-commercial use will normally be granted under the condition that reference is made to ECMWF. The information within this publication is given in good faith and considered to be true, but ECMWF accepts no liability for error, omission and for loss or damage arising from its use. Estimating low-frequency variability and trends in atmospheric temperature… ERA Report Series No.15-Rev.1