Reima Eresmaa

Reima Eresmaa
Finnish Meteorological Institute · Meteorology Unit

PhD
Senior Scientist at the Finnish Meteorological Institute

About

45
Publications
3,939
Reads
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438
Citations
Citations since 2016
9 Research Items
267 Citations
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
Additional affiliations
January 2022 - present
Finnish Meteorological Institute
Position
  • Senior Researcher
May 2021 - December 2021
Finnish Meteorological Institute
Position
  • Group Leader
August 2020 - April 2021
Finnish Meteorological Institute
Position
  • Researcher
Education
January 2002 - December 2007
University of Helsinki
Field of study
  • Meteorology
September 1996 - November 2001
University of Helsinki
Field of study
  • Meteorology

Publications

Publications (45)
Article
The operational assimilation of Infrared Atmospheric Sounding Interferometer (IASI) radiances at the European Centre for Medium-range Weather Forecasts (ECMWF) relies primarily on the use of clear data either in completely cloud-free locations or restricting the assimilation to channels that are insensitive to underlying cloud. Prior to the data as...
Article
The operational assimilation of the Cross-track Infrared Sounder (CrIS) radiances in a four-dimensional variational framework at the European Centre for Medium-range Weather Forecasts (ECMWF) is presented. Currently onboard the Suomi National Polar-orbiting Partnership (S-NPP) polar satellite, CrIS provides radiance data on 1,305 channels in three...
Article
Meteorological satellites launched as part of the Russian space programme have not been widely used in global numerical weather prediction (NWP) to date. There is particular interest in the Meteor‐M series of sun‐synchronous spacecraft, as it is anticipated that future launches will operate in currently unobserved orbital planes complementary to th...
Article
The Suomi National Polar-orbiting Partnership (SNPP) cross-track infrared sounder (CrIS) has provided critical observations for environmental applications for nearly ten years. However, on 26 March 2019, the Joint Polar Satellite System (JPSS) interface data processing segment (IDPS) stopped producing the operational SNPP CrIS sensor data record (S...
Article
Full-text available
ECMWF Newsletter No. 155 - Spring 2018 https://www.ecmwf.int/en/newsletter/155/meteorology/cera-sat-coupled-satellite-era-reanalysis
Poster
Full-text available
ECMWF has a long record of producing comprehensive re-analyses to provide consistent descriptions of global atmospheric state over extended periods of time. The ongoing trend in the re-analysis is towards increased level of coupling between atmospheric, ocean, land, and sea ice components of the Earth system. At ECMWF, a coupled assimilation system...
Poster
Full-text available
The European Centre for Medium-range Weather Forecasts (ECMWF) assimilates infrared radiances from four polar-orbiting satellites. There was a major revision to the operational use of Infrared Atmospheric Sounding Interferometer (IASI) and Cross-track Infrared Sounder (CrIS) radiances in November 2016. Substantial changes were made in observation e...
Presentation
Full-text available
Recent progress in the use of infrared radiance data over land surfaces in numerical weather prediction
Technical Report
Full-text available
We have compiled a new diverse profile database using short-range forecasts from the currently operational version of the Copernicus Atmosphere Monitoring Service (CAMS) forecasting system. The profiles are given in a 60-level vertical grid extending from surface up to 0.1 hPa. The database consists of eight subsets. While one subset is produced by...
Article
This paper investigates the use of an updated observation error covariance matrix for IASI in the ECMWF system. The new observation error covariance matrix is based on observation-space diagnostics and includes inter-channel error correlations, but also assigns significantly altered error standard deviations. The update is investigated in detail in...
Conference Paper
Full-text available
Only a handful of hyperspectral water vapour channels (HWVC) of Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) are actively used in the 4D-Var assimilation system of the European Centre for Medium-range Weather Forecasts. Two approaches are presented with the aim at making the assimilation of HWVC more a...
Technical Report
Full-text available
A database consisting of vertical profiles of atmospheric parameters has been created at the European Centre for Medium-range Weather Forecasts (ECMWF) using short-range forecasts originally produced for the Monitoring Atmospheric Composition and Climate (MACC) project. The database consists of 40,000 vertical profiles, given on 60 model levels, an...
Conference Paper
Full-text available
Output of cloud detection for the Advanced Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) are intercompared in a statistical sense in the context of the Integrated Forecast System, run at the European Centre for Medium-range Weather Forecasts. Two major differences are found. First, completely clear field-of-views a...
Conference Paper
Full-text available
Assimilation experiments with short-wave (SW) radiance data of the Advanced Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Inteferometer (IASI), carried out at the European Centre for Medium-range Weather Forecasts (ECMWF) are presented. SW radiance data are demonstrated to have a large potential for analysis of lower-and mid-tropospheri...
Article
Full-text available
This article discusses the pre-operational development for data assimilation of radial wind observations in the High Resolution Limited Area Model (HIRLAM) at the Finnish Meteorological Institute (FMI). The HIRLAM variational data assimilation system includes all the needed tools for exploitation of radial wind observations. A measurement task desi...
Chapter
Space-borne remote sensing techniques are widely used today to investigate the atmosphere, both by operational and experimental instruments on a large number of satellites. Sensors operating in the microwave range, defined as being wavelengths from 10 to 0.1cm, frequency 3–300GHz (microwaves also comprise sub-millimetre waves or frequencies up to 3...
Article
Ground-based receiver networks of the Global Positioning System (GPS) provide observations of atmospheric water vapour with a high temporal and horizontal resolution. Variational data assimilation allows researchers to make use of zenith total delay (ZTD) observations, which comprise the atmospheric effects on microwave signal propagation. An obser...
Article
Full-text available
The demand for geodetic time series that are accurate and stable is increasing. One factor limiting their accuracy is troposphere refraction, which is hard to model and compute with sufficient resolution, both in time and space. We have studied the effect of numerical weather model (NWM)-derived troposphere slant delays and the most commonly used m...
Article
Doppler radar radial wind observations are modelled in numerical weather prediction (NWP) within observation errors which consist of instrumental, modelling and representativeness errors. The systematic and random modelling errors can be reduced through a careful design of the observation operator (Part I). The impact of the random instrumental and...
Article
An observation operator for Doppler radar radial wind measurements is developed further in this article, based on the earlier work and considerations of the measurement characteristic. The elementary observation operator treats radar observations as point measurements at pre-processed observation heights. Here, modelling of the radar pulse volume b...
Article
Numerical weather prediction (NWP) model output can be used for derivation of tropospheric delay correction in order to decrease positioning errors of Global Navigation Satellite System (GNSS) applications. In precise geodetic positioning it is possible to make use of corrections that are derived separately for all GNSS signal paths. Due to the lar...
Article
Full-text available
The demand of accurate and stable time series of geodetic parameters is increasing. One factor limiting the accuracy is the troposphere, since it is hard to model and compute with sufficient resolution, both in time and space. We have studied the effect of numerical weather model (NWM) derived troposphere slant delays to most commonly used mapping...
Article
Full-text available
1] Implementation of an observation-modeling algorithm is necessary in order to make use of Slant Delay (SD) observations, processed from ground-based Global Positioning System (GPS) measurements, in Numerical Weather Prediction (NWP). This article introduces an algorithm for SD observation modeling. The algorithm is an extension of radio-occultati...
Article
Validation of mesoscale numerical weather prediction models calls for high-resolution observations. Conventional data sources, such as radiosonde data, provide a reliable benchmark but their spatial resolution is insufficient for model validation in the kilometric scale. Doppler radar radial wind observations are used in this study as an alternativ...
Article
Doppler radars provide measurements of the radar radial wind component at high spatial and temporal resolution. The variational data-assimilation framework enables direct use of these measurements in numerical weather prediction models. Bias estimation of Doppler-radar radial winds requires special attention because of the azimuthal scanning strate...
Article
Full-text available
The ground-based measurements of the Global Positioning System (GPS) allow estimation of the tropospheric delay along the slanted signal paths through the atmosphere. The meteorological exploitation of such slant delay (SD) observations relies on the hypothesis of azimuthal asymmetry of the information content. This article addresses the validity o...
Article
Tropospheric delay affects the propagation of the microwave signals broadcast by the Global Positioning System (GPS) satellites. Geodetic processing software enable estimation of this effect on the slanted signal paths connecting the satellites with the ground-based receivers. These estimates are called slant delay (SD) observations and they are po...
Article
Full-text available
The ground-based measurements of the Global Positioning System (GPS) allow estimation of the tropospheric delay along the slanted signal paths through the atmosphere. The meteorological exploitation of such slant delay (SD) observations relies on the hypothesis of azimuthal asymmetry of the information content. This article addresses the validity o...
Article
Full-text available
The troposphere is one of the most significant sources of error in precise GPS (Global Positioning System) positioning solutions nowadays. Uncertainties in troposphere estimation distort the height component especially. We have implemented the troposphere slant delays derived from a numerical weather prediction model to GPS processing. In this case...
Article
Full-text available
An observation operator for the Global Positioning System (GPS) Slant Total Delay (STD) observations is developed. The operator is implemented in the High Resolution Limited Area Model (Hirlam) for data assimilation of tropospheric humidity information contained in the geodetic estimates of microwave signal phase delays.The observation operator int...
Article
An observation operator for the Global Positioning System (GPS) Slant Total Delay (STD) observations is developed. The operator is implemented in the High Resolution Limited Area Model (HIRLAM) for data assimilation of tropospheric humidity information contained in the geodetic estimates of microwave signal phase delays. The observation operator in...
Article
In this paper, we present new methods and estimates of the spatial (horizontal) covariance of the ground-based Global Positioning System Zenith Delay observation errors. An algorithm is developed which enables estimation of the observation error covariance as a linear combination of innovation covariances of Zenith Total Delay (ZTD) at ground-based...
Article
Full-text available
In this paper, we present new methods and estimates of the spatial (horizontal) covariance of the ground-based Global Positioning System Zenith Delay observation errors. An algorithm is developed which enables estimation of the observation error covariance as a linear combination of innovation covariances of Zenith Total Delay (ZTD) at ground-based...
Article
Full-text available
The microwave signals continuously broadcasted by the Global Navigation Satellite System (GNSS) satellites are influenced by the ionospheric and tropospheric effects as they travel through the atmosphere to the ground-based receivers. Using a sufficiently dense network of GNSS receivers, the impact of the neutral atmosphere, i.e. tropospheric delay...
Article
Full-text available
Ground based GPS Zenith Total Delay (ZTD) observations are known to suffer from spatial error covariances. Unless explicitly taken into account in the data assimilation, these error covariances are expected to degrade the quality of the obtained analysis, as unrealistically large weight is given to this specific data source. A method for estimating...
Article
Full-text available
Data assimilation provides an initial atmospheric state, called the analysis, for Numerical Weather Prediction (NWP). This analysis consists of pressure, temperature, wind, and humidity on a three-dimensional NWP model grid. Data assimilation blends meteorological observations with the NWP model in a statistically optimal way. The objective of this...

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Projects

Projects (5)
Project
Improve the assimilation of satellite data into NWP models.
Archived project
Improve the assimilation of satellite data into NWP models.