Inte

rnati

on

al G

NS

S S

erv

ice (

IGS

)

Tro

po

sp

here

Pro

du

cts

an

d W

ork

ing

Gro

up

Acti

vit

ies

C H

ackm

an

1, G

uerg

an

a G

uero

va

2,

S B

yra

m1,

J D

ou

sa

3 a

nd

U H

ug

en

tob

ler4

1U

nited S

tate

s N

aval O

bserv

ato

ry,

Washin

gto

n, D

C U

SA

2S

ofia U

niv

ers

ity,

Sofia,

Bulg

aria

3G

eodetic O

bserv

. P

ecný,

Czech R

epublic

4T

echnis

che U

niv

ers

ität M

ünchen

, M

unic

h, G

erm

any

guero

va@

phys.u

ni-sofia.b

g

christine.h

ackm

an@

usno.n

avy.m

il

2

FIG

Work

ing W

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015 P

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7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

Agenda

•IG

S o

verv

iew

: m

issio

n,

receiv

er

netw

ork

•W

hy I

GS

estim

ate

s t

roposphere

dela

y

•IG

S F

inal T

roposphere

Estim

ate

s:

genera

tion,

usage

•IG

S T

roposphere

Work

ing G

roup:

str

uctu

re, m

eetings,

pro

jects

, how

to join

3

FIG

Work

ing W

eek 2

015 P

aper

7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

IGS

overv

iew

(fo

unded 1

994)

•M

issio

n:

•pro

vid

e h

ighe

st-

qualit

y G

NS

S d

ata

, pro

ducts

, se

rvic

es…

•in

supp

ort

of applic

ations b

ene

fiting s

cie

nce, so

cie

ty (

e.g

.,

terr

estr

ial re

fere

nce fra

me, P

NT

, eart

h-s

cie

nce r

ese

arc

h)…

•openly

-availa

ble

basis

•A

ctivitie

s:

•co

ord

inate

glo

ba

l G

NS

S-r

ece

iver

netw

ork

, arc

hiv

ing o

f its d

ata

•pro

duce e

stim

ate

s fro

m those

data

: G

NS

S s

ate

llite

orb

its,

receiv

er

coord

inate

s, eart

h r

ota

tion p

ara

mete

rs, sat/re

ceiv

er

clo

ck

valu

es, io

no

/tro

po

valu

es…

•w

ork

ing g

roups: im

pro

ve s

cie

nce to im

pro

ve e

stim

ate

s

•T

o learn

more

: htt

p:/

/igs.o

rg

4

FIG

Work

ing W

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015 P

aper

7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

IGS

receiv

er

netw

ork

, data

analy

sis

•400+

perm

anent

continuously

-

opera

ting d

ual-

frequency c

arr

ier-

phase r

eceiv

ers

•R

ecord

one o

r m

ore

of:

GP

S, G

LO

, G

AL,

BeiD

ou,

QZ

SS

,

SB

AS

•D

ata

arc

hiv

es

(public

ly-a

ccessib

le):

•F

our

glo

bal IG

S

data

cente

rs

•R

egio

nal data

cente

rs

•IG

S a

naly

sis

cente

rs p

rocess m

easure

ments

, contr

ibute

“pro

ducts

” (e

.g.,

orb

its)

to I

GS

AC

Coord

inato

r, w

ho

pro

duces o

ffic

ial IG

S p

roducts

:

•ultra

s (

NR

T);

rapid

s (

24

-h late

r);

finals

(best)

5

FIG

Work

ing W

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015 P

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7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

Why IG

S e

stim

ate

s tro

po

sp

he

re d

ela

y

•O

rigin

al re

ason:

“nuis

ance p

ara

mete

r” –

must estim

ate

to

achie

ve c

m-

or

mm

-level G

NS

S p

ositio

nin

g

•2.2

m @

ze

nith; te

ns o

f m

@ low

ele

vation (

e.g

., 1

5 o

r 7 d

eg

)

•Z

TD

GN

SS =

ZT

Ddry +

ZT

Dw

et

•Z

TD

dry:

~2

m, ca

n m

odel

•Z

TD

wet:

0.1

-0.2

5 m

, ch

ange

s too q

uic

kly

/locally

to m

odel ->

must

estim

ate

fro

m G

NS

S o

r get fr

om

, e.g

., W

VR

•B

ut

now

: use Z

TD

GN

SS -

> Z

TD

wet ->

PW

V

•A

tmospheric s

cie

nce!

•L

ow

-late

ncy, hig

h-d

ensity P

WV

: w

eath

er

fore

casting

•D

eca

des-l

ong r

eco

rd, 300+

sites w

orldw

ide, valu

es e

very

fiv

e

min

ute

s: clim

ate

stu

die

s

6

FIG

Work

ing W

eek 2

015 P

aper

7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

IGS

Fin

al T

roposphere

Estim

ate

s

•U

SN

O/D

r S

Byra

m g

ene

rate

s

•O

ne 2

4 h

r file

per

IGS

sta

tion

•

ZT

D,

gra

die

nts

every

5 m

in

•325

-6 s

tations/d

, 2013-4

•C

om

pute

d u

sin

g B

ern

ese G

PS

S

W, G

MF

, P

PP

usin

g IG

S F

inal

Orb

its/E

OP

s/S

V c

locks

•T

hus ~

21 d

late

ncy

•U

sed b

y s

cie

ntific r

esearc

hers

as r

efe

rence (

e.g

. W

an

g e

t al.

2013

* ra

dio

sonde

stu

dy)

•12.3

M d

ow

nlo

ad

s in 2

014

•ftp://c

ddis

.gsfc

.nasa.g

ov/g

ps/p

roducts

/tro

posphere

/zpd

Num

ber

of

qualit

y-c

hecked IG

S F

inal

Tro

posp

here

Estim

ate

file

s s

ubm

itte

d t

o

IGS

per

measure

ment

day.

20

0

25

0

30

0

35

0

40

0

03

65

73

01

09

51

46

0

# receivers for which files submitted

da

ys

sin

ce 1

Ja

n 2

01

1

Nu

mb

er,

QC

-ed

Tro

po

Fil

es

Su

bm

itte

d t

o I

GS

20

11

me

an

: 3

22

20

12

me

an

: 3

02

20

13

me

an

: 3

25

20

14

me

an

: 3

26

improvedresults screening

update station list

*Wang, J.

et a

l.,

“Ra

dia

tion d

ry b

ias c

orr

ectio

n o

f V

ais

ala

RS

92

hu

mid

ity d

ata

an

d its

im

pa

cts

on

his

torica

l

rad

ioso

nde

da

ta,”

J A

tmo

sp

h a

nd

Oce

an

ic T

ech

, 3

0:1

97-2

14, 2

01

3.

Exam

ple

: IG

S F

inal Z

TD

, 29 J

une 2

012

CE

DU

DA

V1

KO

KB

PO

L2

TH

U3

U

SN

3

19

00

20

00

21

00

22

00

23

00

24

00

25

00

26

00

00

.25

0.5

0.7

51

MM

FR

AC

TIO

N O

F D

AY

TO

TAL

ZE

NIT

H T

RO

PO

SP

HE

RE

DE

LAY,

30

JU

NE

20

12

CE

DU

DA

V1

KO

KB

PO

L2T

HU

3U

SN

3

FIG

Work

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015 P

aper

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ofia, B

ulg

aria; 18 M

ay 2

015

7

8

FIG

Work

ing W

eek 2

015 P

aper

7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

Usin

g I

GS

FT

Es:

su

btleties

•“R

epro

cessin

g”

cam

paig

ns:

•IG

S a

dop

ts n

ew

physic

al m

odels

->

ch

ange

s Z

TD

estim

ate

s

(thoug

h s

am

e a

tmosph

ere

) ->

co

mplic

ate

s long

-term

stu

die

s

•T

o a

ddre

ss: re

pro

cess e

ntire

tim

espan o

f IG

S G

NS

S

measure

ments

usin

g o

ne, best-

to-d

ate

model se

t

•“R

epro

1”:

ftp

://c

ddis

.gsfc

.nasa.g

ov/g

ps/p

roducts

/zpd/r

epro

1

•“R

epro

2”:

will

do w

hen R

epro

2 o

rbits/c

locks/E

OP

s c

om

ple

te

•U

pcom

ing im

pro

vem

ents

to I

GS

FT

Es:

•R

educe d

ay-b

oun

dary

dis

co

ntinuitie

s (

no

n-p

hysic

al fe

w-m

m Z

TD

-

valu

e jum

ps b

etw

ee

n e

nd o

f one 2

4-h

r file

, begin

nin

g o

f next)

•U

pgra

de to n

ew

er

vers

ion o

f B

ern

ese S

W, new

er

models

IGS

Tro

po

sphere

Work

ing

Gro

up

lM

issio

n:

impro

ve a

ccura

cy,

usabili

ty o

f G

NS

S

troposphere

estim

ate

s

lM

em

bers

: 50+

worldw

ide;

all

are

welc

om

e!

lT

wo m

eetings/y

r (s

imulc

ast

usin

g g

oto

meeting.c

om

):

lD

ece

mber:

sp

linte

r @

Am

. G

eophysic

al U

nio

n F

all

Meeting

lS

pring/S

um

mer:

either

IGS

Work

shop o

r sp

linte

r @

EG

U

lM

ajo

r activitie

s:

lW

ork

ing g

roup p

roje

cts

(n

ext page

).

lC

oord

inate

techn

ica

l se

ssio

ns (

ple

nary

, poste

r) a

t IG

S W

ork

sho

p.

lP

lenary

: th

ree o

ral pre

senta

tions,

big

-pic

ture

pro

jects

lP

oste

r: g

oal =

foste

r te

chnic

al exchange -

> s

eek m

axim

um

part

icip

ation

lLin

ks t

o 2

014 I

GS

Work

shop

contr

ibutions in p

rinte

d v

ers

ion o

f th

is p

resenta

tion

FIG

Work

ing W

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015 P

aper

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aria; 18 M

ay 2

015

9

IGS

TW

G p

roje

cts

FIG

Work

ing W

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015 P

aper

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S

ofia, B

ulg

aria; 18 M

ay 2

015

10

Auto

mate

d,

continuous c

om

pari

sons o

f

tropo e

stim

ate

s f

rom

independe

nt

techniq

ues (

GN

SS

, V

LB

I, r

adio

sondes…

)

•C

om

pari

son o

f answ

ers

yie

lds b

ett

er

uncert

ain

ty e

stim

ate

s -

> im

pro

ves

accura

cy

•P

rim

ary

develo

pm

en

t @

GO

P;

contr

ibu

tions f

rom

GF

Z,

US

NO

, m

ore

•P

art

ially

fundin

g,

CZ

-US

Konta

kt

II

gra

nt

# L

H14089

•C

om

ple

te 2

016

clic

k-a

ble

sta

tion m

ap

, lis

t

gra

phs u

p t

o s

ix

sta

tions w

ith

multip

le

techniq

ue

com

parisons

user

defined

com

parison

gra

ph

Supp

ort

of

trop

o_

sin

ex (

ZT

D-d

issem

ination)

form

at

sta

ndard

ization

•A

d-h

oc f

orm

at

evolu

tion in d

iffe

rent

geodetic

com

munitie

s

•IG

S T

ropo

WG

mem

bers

R P

acio

ne

, J D

ousa

spearh

eadin

g C

OS

T A

ction G

NS

S4S

WE

C

WG

3 e

ffort

to r

edefin

e/e

xpand f

orm

at

•S

tatu

s:

just

sta

rted F

all

2014

11

FIG

Work

ing W

eek 2

015 P

aper

7696

S

ofia, B

ulg

aria; 18 M

ay 2

015

Conclu

sio

n: jo

in u

s!

Fo

r m

ore in

form

ati

on

on

…

•IG

S: http://igs.o

rg

•IG

S F

inal T

rop

osphere

Estim

ate

s:

•D

ow

nlo

ad h

ere

: ftp://c

ddis

.gsfc

.nasa.g

ov/g

ps/p

roducts

/tro

posph

ere

/zpd

•Q

uestions a

bout

them

?

•D

r S

ha

ryl B

yra

m:

sh

ary

l.b

yra

m@

usn

o.n

avy.m

il

•D

r C

hri

stin

e H

ackm

an

: ch

ristin

e.h

ackm

an

@usno

.na

vy.m

il

•IG

S T

rop

osphere

Work

ing G

roup:

•Q

uestions:

christine.h

ackm

an@

usno.n

avy.m

il

•W

ebsite (

under

develo

pm

ent)

: http://igs.o

rg/p

roje

cts

-work

ing

-gro

ups/tw

g

•Join

em

ail

list: h

ttp://igscb.jpl.nasa.g

ov/m

ailm

an/igs-t

wg

Tha

nk y

ou f

or

your

att

ention!

Extr

a s

tuff

(as n

eeded?)

FIG

Work

ing W

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2015 P

aper

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aria; 18 M

ay 2

015

12

13

FIG

Work

ing W

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aper

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S

ofia, B

ulg

aria; 18 M

ay 2

015

Exam

ple

:

Gra

die

nt of 1

mm

asym

metr

y o

f

1 m

m a

t z=

38

asym

metr

y

15 m

m a

t

z=

75

tilt o

f 1.5

′

pro

jection o

f ze

nith

dela

y v

ecto

r: 1

mm

Tro

posphere

Gra

die

nts

hydro

sta

tic

dela

y

(mod

elle

d)

wet dela

y

(estim

ate

d)

NS

and E

W

gra

die

nts

(estim

ate

d)

sla

nt dela

y

(mea

su

red)