my activities - tu wien · 2017. 6. 12. · nwp & da numerical weather prediction (nwp) models,...

My ActivitiesNATALIA DYMARSKA, HOHE WAND, 24.05.2017

Former workMaster studies (master defence: July 13th, 2016)

The first trials of GNSS tomograpy data assimilation (June 2016)

STD operator (holidays + a few months after)

01.06.2017 NATALIA DYMARSKA 2

NWP & DANumerical Weather Prediction (NWP) models, e.g., the Wearher Research and Forecastig(WRF) model, are designed for both atmospheric research and operational forecasting needs

Observations are fed into the NWP model (data assimilation).

Data Assimilation (DA) has two main goals:o Optimally blends information from observations and model to produce an accurate and physically

consistent estimate of the initial state of the atmosphere and of the other components of the EarthSystem

o Assessing the uncertainty of our estimate of the initial state.


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

Observation operatorHas to be provided for each type of observations, we want to assimilate

A function (or a set of functions), which allows to compute the observation equivalent fromthe model variables

Allows to compare observations and model background („O-B”).


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

ZTD QualityThe thesis title: „GNSS tropospheric delay as a meteorological data source for the Numerical Weather Prediction models”

An analysis of the quality of the Zenith Total Delay (ZTD) estimated in the near-real time (NRT) at the Wrocław University of Environmental and Life Sciences (WUELS)


Former work

Master studies

GNSS Tomography

data assimilation

STD operatorFig. The results of ZTDWUELS – ZTDUSNO, ZTDWUELS – ZTDRS, ZTDWUELS – ZTDLIGIG, ZTDRS – ZTDUSNO, ZTDLIGIG – ZTDUSNO [m] at WROC station in the period from 20 February 2015 to 31 December 2015.

Dymarska, N., Rohm, W., Sierny, J., Kapłon, J., Kubik, T., Kryza, M.,Jutarski, J., Gierczak, J., Kosierb, R. (2017). An assessment of the quality ofnear-real time GNSS observations as a potential data source formeteorology. Meteorol. Hydrol. Water Manag., Vol. 5, 1.

NRT ZTD Assimilation

Changes the initial conditions of the model

Improves the relative humidity forecasts in the lower part of the troposphere


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

Model WRF

Horizontal resolution 36 km x 36 km

Grid size 80 NS, 70 EW

Vertical layers 35

Initial and boundary conditions NCEP FNL (Final) 1° x 1°

Assimilation module / mode WRF DA / 3D-Var

Assimilation window 3 h

Stations / observations122 stations ASG-EUPOS / NRT ZTD

Simulation period 01-30 May 2013

Model run 00, 06, 12, 18

Forecasts lead time 24 hours

Wet refractivity assimilationThe effect of the atmosphere on GPS signals appears as an extra delay in the measurementof travel time from the transmitters to the receivers;

GNSS tomography allows to derive wet refractivity fields (𝑁𝑁𝑤𝑤𝑤𝑤𝑤𝑤) from Slant Wet Delays(SWDs), which can be assimilated into the Numerical Weather Prediction (NWP) models;

Calculation of the complete value of refractivity, as a sum of the wet and the non-hysrostatic(dry) part;

The assimilation of the tomography outputs into WRF Data Aassimilation system (WRF DA)using available module, dedicated to other type of observations (radio occultation).


Former work

Master studies

GNSS Tomography

data assimilation

STD operator


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

Wet refractivity assimilation

Comparison of the 𝑁𝑁𝑤𝑤 computed from RS, WRF, WRFafter assimilation, and TOMO output (left).

Conclusion: The assimilation of tomography outputs using RO

module is possible, In the result of the assimilation, the initial

conditions of the model are changed, Comparing with radiosonde (RS) observations, we

noticed some positive impact of the refracitvityassimilation for the relative humidity (RH)forecasts.

STD observation operatorGNSS Slant Total Delays (STD) are the signal delays between satellites and receivers coused by thepresence of the atmosphere. They are strictly related to the refractivity, hence can be calculated usingmeteorological quantities.

Development of the GNSS STD assimilation operator in the WRF model for variational methods requiresthe construction of the operators:• non-linear (NL),• tangent linear (TL),• and adjoint (ADJ).


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

STD NL operatorNon-linear operator is based on the raytracing technique (left). Refractivity on the station is calculated according to the formula:

𝑁𝑁0 = 𝑘𝑘1𝑝𝑝 − 𝑒𝑒𝑇𝑇

� 𝑍𝑍𝑑𝑑−1 + 𝑘𝑘2𝑒𝑒𝑇𝑇

+ 𝑘𝑘3𝑒𝑒𝑇𝑇2

� 𝑍𝑍𝑣𝑣−1

The elevation angle of the ray is corrected based on the refractivity and the process is repeated on the consecutive layers.

STD is the sum of delays calculated for the all segments.


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

STD TL and ADJ operatorsConstruction of the TL and ADJ is necessary for the minimisation of the cost function.

The TL is derived from NL by linearisation.

The ADJ is derived from the TL by transposition.

The linearisation of the complex NL operator is a challenging task; we consider to introduce somesimplifications, e.g. reduction of the vertical resolution to the WRF layers only (no vertical interpolationneeded).

Those tasks will be accomplished by the GNSS&Meteo working group at the WUELS.


Former work

Master studies

GNSS Tomography

data assimilation

STD operator

Current activities & Future workPh.D. Studies

ESA Atmosfiller project

GNSS Tomograpy data asssimilation


Radio Occultation techniqueOccultation means that a celestial object iseclipsed by an (apparently) larger one.

Radio Occultation (RO) has been developedin the 1960s for the study of planetaryatmosphere

The extremly stable radio signals of the GPSsatellites (triggered by on board atomicclocks) allowed to apply the method to theEarth’s atmosphere

Presentation: „Observing Atmosphere andClimate with GNSS Radio Occultaton”, givenby Prof. Ulrich Foelsche, 01 March 2017


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Radio Occultation techniqueRO as a remote sensing technique uses areceiver in a low-Earth orbit ( ~700 kmaltitude) to track signals from GNSSinstruments at about 20,000 km altitude.

The occultation occurs when the geometry ofthe GPS and LEO satellites align so that thetransmitted signals pass through the planet’satmosphere.

If a planet has no atmosphere, the beam willremain in a straight line. If the planet has anatmosphere, the signal will be refracted, orbent.


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Radio Occultation geometry


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Radio Occultation techniqueAtmospheric Phase Delay:

~1 mm Mesopause

~20 cm Stratopause

~20 m Tropopause

~1-2 km Surface

RO missions:o COSMICo CHAMPo GRACEoMetOp


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Phase delay•Orbit Information, Ionospheric Correction

Atmospheric Delay

•Orbit information

Bending Angle

•Abel Transform

Refractivity•Density • Temperature/

Water vapor

Radio Occultation – why so important?In the middle of an ocean, surface and radiosonde observations are typically not available;traditional infrared satellite sounders cannot penetrate through clouds, so they cannotprovide information on conditions below the clouds.

Radio occultation soundings provide information through the entire troposphere andstratosphere.

When the data are included in forecast models, they lead to significant improvements innumerical weather prediction (e.g. successful capture of cyclon genesis, better depiction ofcyclone evolution)


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

COSMIC MissionThe first COSMIC mission was launched in 2006as a collaboration between the UniversityCorporation for Atmospheric Research (UCAR)and the Taiwan National Space Organization(NSPO)

COSMIC provides between 1500 and 2500profiles of the atmosphere each day – theseprofiles support operational forecasting as wellas numerous atmospheric research application.


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

COSMIC Data


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Data available on: http://cdaac-www.cosmic.ucar.edu/cdaac/products.html

Devided on levels:o Level0 – Raw datao Level1a – Raw data, which have undergone reformatting and splitting up into easier to process unitso Level1b – GPS and LEO orbit files, Excess phase files, Occultation tableso Level2 – Refractivity profiles, „Dry” and moisture-corrected temperature and pressure profiles, Moisture

profiles, Electron density profileso Level3 – A grid of averaged radio occultation datao Output – A directory used to hold output from all programs used to process data

http://cdaac-www.cosmic.ucar.edu/cdaac/products.html

Raytracing: LEO and GPS satellites


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Raytracing: data preparation


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Program:

RADIATE, given by Hofmeister (2016)

Input data:

COSMIC, Level 1b

Simple scripts:

Creating the new „AZEL” file containg the RO data, incl. Azimuth and Elevation of the GPS satellite,

Providing the coordinates of the LEO satellite to the „vlbi.ell” file.

Raytracing: running error


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Interpolation issues:

% *calculate_refr_ind_HD_slim_gridwise_global_ECMWFmin* is a function to calculate the refractive% index profiles using the% meteorologic values derived for example from a grib-file from the ECMWF.% The vertical resolution (height level resolution) from the ECMWF data will be increased and% above the highest ECMWF level extrapolation using a standard atmosphere will be carried out.% The lowest interpolation height level is determined according to the minimum height of all% observing stations in a specific epoch in order to avoid interpolation for levels that will% never be used later during the ray-tracing.% The highest interpolation height level is defined (e.g. 84 000 m).



Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

SITE X [m] Y [m] Z [m] LAT [°] LON [°] Height [m]

001_1 -4086468.9937 -2548632.6349 5351920.3338 48.1857 211.9508 833549.46

Scan Source Time Site Azim. [°] Elev. [°] P[hPa]T

[°C]STD[m]

Wet mf

ZHD[m]

ZWD[m]

1 NaN 2014.05.01-00:02:24.5 000_1 7.65987 -25.93014 NaN NaN 0 NaN 0 0

Change of the top of the standard atmosphere



Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

RADIATE program, provided by Hofmeister (2016); VLBI data

104



Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

COSMIC (Level1b) data

104

How to do the raytracig using RO data?

The proper defining the elevation angle of the ray path at the next intersection point

Maybe using the perigee point (the GPS RO profile point closest to the Earth’s surface) –provided by COSMIC in occultation table file!

Providing my own RO refractivity profiles – what is a goal?



Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

ESA Atmosfiller ProjectThe title of the project: „Completing the atmospheric sounding system with GNSS and platform integrated sensors”

My task: An assimilation of the ZTD/ZWD observations and chemical aerosols:o Particulate matters (PM2.5 and PM10),o COx (carbon oxide)o NOx (nitrogen oxide)o Temperature


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Software installation Virtual Machine: Linux debian 3.16.0-4-amd64 #1 SMP Debian 3.16.39-1 (2016-12-30) x86_64

GNU/Linux WRF v. 3.8.1 gfortran compiler, gcc, cpp, csh, perl, sh, netCDF package, MPICH, JasPer, libpng, zlib WRF-Chem v. 3.8.1 FLEX library GSI (Grid Point Statistical Interpolation System) v. 3.5


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation Fortran compiler version C compiler version

Intel only ifort 16.0.1, 15.0.1, 13.0.1, 12.1.5, 12.1.4 icc

Intel & gcc ifort 16.0.1, 15.0.1, 13.0.1, 12.1.5, 12.1.4 gcc 4.8.2, 4.4.7

PGI only pgf90 16.1, 15.10, 15.7, 15.1, 14.10, 14.9, 14.7, 13.9, 13.3

pgcc

PGI & gcc pgf90 16.1, 15.10, 15.7, 15.1, 14.10, 14.9, 14.7, 13.9, 13.3

gcc 4.8.2

GNU only gfortran 6.3.0, 5.3.0 4.9.2 (earilier) gcc 6.3.0, 5.3.0 4.9.2 (earlier)

Assimilation of ZTD (WRF DA) and aerosols (GSI)


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

WRF-Chem Input Data:o Anthropogenic emissionso Biogenic Emissionso Biomass burning emissionsso Volcanic emissions data files

GSI model (release 3.5):o Developed to analyze chemical

observationso For use with GSI, all observations

need to be in PrepBUFR/BUFR formato Currently can do the following

chemical analyses (table on the right).

Case Chemical ModelBacground

species Observations

1 WRF-Chem GOCART MODIS AOD

2 WRF-Chem GOCART PM2.5

3 WRF-Chem PM2.5 PM2.5

4 CMAQ CMAQ PM2.5

WRF WRF DA

WRF CHEM GSI

Assimilation of GNSS tomography productsAssimilation of the wet refractivity fromtwo different GNSS tomography models:• TU Wien (Gregor Möller)• TOMO-WUELS (Estera Trzcina)

Data period: 29 May – 14 June 2013

Data domain: East Germany and thewestern part of Czech Republic

WRF domain: 36 km (nested: 12 km) gridspace resolution

Assimilation settings: gpsref (radiooccultation) operator and radiosondeoperator


Current Activities

Ph.D. studies

ESA project

GNSS Tomography

Data Assimilation

Training courses & conferencesECMWF Data Assimilation Course, 27-31 March 2017, Reading, UK

The five-day module focuses on describing data assimilation methods and general aspects of assimilatingobservations.

Poster: Dymarska N., Rohm W., Kryza M.: An Assimilation of the NRT GNSS ZTD into the WRF model(3DVar).

Pre and Post Data Assimilation Courses at the University of Reading, UKo Pre-course: An introduction to data assimilation methods (23-24 March 2017)o Post-course: Computing „Hands on” course (3-4 April 2017)

EGU General Assembly 2017

Poster: Trzcina E., Rohm W., Dymarska N.: GNSS tropospheric tomography in Near-Real Time mode as avaluable data source for Numerical Weather Prediction models.


Thank you for your attention!

NATALIA DYMARSKA

01.06.2017 32

My ActivitiesFormer workNWP & DAObservation operatorZTD QualityNRT ZTD AssimilationWet refractivity assimilationWet refractivity assimilationSTD observation operatorSTD NL operatorSTD TL and ADJ operatorsCurrent activities & Future workRadio Occultation techniqueRadio Occultation techniqueRadio Occultation geometryRadio Occultation techniqueRadio Occultation – why so important?COSMIC MissionCOSMIC DataRaytracing: LEO and GPS satellitesRaytracing: data preparationRaytracing: running errorRaytracing: LEO and GPS satellitesRaytracing: LEO and GPS satellitesRaytracing: LEO and GPS satellitesRaytracing: LEO and GPS satellitesESA Atmosfiller ProjectSoftware installationAssimilation of ZTD (WRF DA) and aerosols (GSI)Assimilation of GNSS tomography productsTraining courses & conferencesThank you for your attention!

my activities - tu wien · 2017. 6. 12. · nwp & da numerical weather prediction (nwp) models,...

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