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Analysis of the Temporal and Spatial Variability of the Wet Troposphere at a Local Scale by High-rate PPP Using a Dense GNSS Network

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The objective of this work is to study and characterize the temporal and spatial variability of water vapor at a local scale, i.e. less than 10 km, by analyzing wet tropospheric delays estimated by a dense GNSS network. Experiments using high-rate (30 s and 5 s) observations are conducted in order to investigate also the short periodic refractivity fluctuations induced by turbulence, expected to be in the range of minutes to seconds. The effects induced by interpolation errors of satellite clocks with high-rate observations are investigated. The GPS-derived precipitable water vapor (PWV) is validated by comparison with the PWV measured by radiosondes and a radiometer, obtaining differences of about 2 mm in RMS. The distribution of PWV is studied by geostatistics (kriging) and turbulence analyses. Spatial and temporal structure functions are computed for both zenith wet delays and show power-law behaviors varying between 5/3 and 2/3, consistently with the Treuhaft-Lanyi model (i.e. a long baseline approximation for Kolmogorov turbulence theory). Power-law behaviors in temporal structure functions result both for long-term variations, with correlation lengths depending on the weather conditions, and for short-term fluctuations, until about 10 seconds; for shorter time lags the structure functions decorrelate into noise.
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Analysis of the temporal and spatial variability
of the wet troposphere at a local scale by
high-rate PPP using a dense GNSS network

Research Institute for Sustainable Humanosphere, Kyoto University
Center for the Promotion of Interdisciplinary Education and Research, Kyoto University
Department of Geophysics, Graduate School of Science, Kyoto University
Department of Communications and Computer Engineering, Graduate School of Informatics, Kyoto University
BIOGRAPHY
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  .&  #  "!  "  
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,,.*/*&,,-$
#&'()!*%"" "
    (!&  #    &  "5  #
&"#&("#
!&  $  &"  !    0$
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  &;$
#<&!"   / #  "
  #  $  %&!  #  
'()!*%" "  ((
&  =!&  #      (!  $(
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!"&*
       &       ;$ #
<&!"      /  #    "
  #  $  %&!  #  
'(  )!*  %    "  ((    $"
"$4"&#(&$
0.*
ABSTRACT
  $>"(#  ""
&!  ! ($ #  (! 
"  "  **      ,  &  $    
!!"&$06*
=!& 42, - 3$(
  ""        (      
!" #"( #" " $ $"
=!"$ # &  "* 
##" "$ ! # ""
4$((*
  0.4(  !"!$    (!  2.?@3  
(  $  "&!      .?@  &  $
      &  $  ##"  #
$&&*$#.?@
$"23$"*!
&! " #"  "&! # $
!4$((
$-AA"#4;
&  2**      $  !!=&  #
&( $" 3*.4$( 
&!  "  #"    $  #  4&
(    "    !    
 " #4& #"
$  ,  "B  #    &      "
#""*
INTRODUCTION
    #  06          
&!&!(06!
$ &!& $ !!"&$ 
&    ""    &!"    (!
($&!"CD*&#
(! &"#& !" #
& #  =&!   !! &"  
!"26?.3&&!($
  #"    (*  7    &  (
&!""!&"
  &        "  "  $  
"&  #      (!&  #  "    
"  #  #  &*  <  "    $
&  &  #    (!      "  "  $
&# 06$&!
"##&#"$(#
(!$#  #& # "B  " $
    6?.  &      #  $
    &      #  (  
!(  &!"  #    !(    
&*
   ##"06  #"(
  !     !!  "  #    
2"324"3"&!*
  "&!    "        &  #
""&(!4"(4
#4* ? "&!"$ &
$# "" 4( ! (
&"&!&##"
$"#($$&#
(!"#" #
#"(=*<!$!!"!$&
    &      !!      &
&& "#"
        !  !"  2    
#"  "  $  (  !3B
(!!""$&
      !&      06  
"*   "   !!" 
0. !" " &!!   
2**      4"(  4#43  ($
$(    (  (        
"!"#"&!!#"**6
&!!  #"  CD      $  &!!  #"
20E3CD*&!!(
   & #     2:/3*  
##"  $    &      
(        !(      !"
!    *            !!
          
&($""*
   2/3 #" " $
"" $ &!!$" :/  4
"(  4#4        "!
*  "    &  #    (!    "
  &  C D#& :/
/&"&(""&!
&   (! "
#!!$&*
WATER VAPOR MONITORING SYSTEM
<    #  F  4#5"  06    
!"#"    #  4  .?@  (
C-D'>"&!#'(
)!*4 " ( $  &
"(#$,G8&2E
3*
Fig. 1   #"(  '>
2  )!3  !  $    B  $"
" ""# " 06

<"("$(0.0;6<
9:%B#!!#0.
$(  $!&  9:
$"*?
 &!&!
#  ""        2:?/3    !"!$
(!2.?@3(*E!&""
#&    7  #  $  /&    !
27/3*!"-""
!($ 7/C8D&!  "
    ""  !  ##"      -  
$(*-""
    !"#"  7/  !"  "  "  #
!! 4 !"! !2...3B 
    #    ""  !(  $  
  06  ("  203    ,  *  $  
&&!"&!#
"$  !!*6  0E !!
    #&  #      !    "  
&  $  &  &  CFD        
#&  #    &  *  6  !!"
&*#
($"C-D
  "    !  #  &!   $  "
0.    (  ! # 
9:  #  &!"    "        
!(          "  "   
""&!*
Table 1."
."# 6
."& ...
&"5 &#
;"&$ ;24#3
7*(* &
.*(* "&
<!"**(* "&
:/(" -G,4-&A
." ,A-
!& 7/2#3
"" 7/,A-2#3
!!#" 0EA
("## ,
A"(.7@ ,H*=
" 0,,*
SYSTEM VALIDATION
!!"&$
(  $  =(  (  $  "&!  
!  &&      
&"(&*"&&
  &  #    (!   "&!      
&  #  .?@  ##"*    (  &&
"&!($"")<,
,$,"$
&  #  &  &&    *    0.4
(.?@&$(
$(  ,    #  (      $  "
&#$
&&    *      $    (  
    &  &      (!
 !"#""   !#
$" $  "$ #
  #&     !# A  "
#*&#
.?@  (  #&  0.  &&  ((  
(#("
#$"("
-I-2E3*!(!!C-D
(!!""&!$
.?@  "  $    &    0.  $
"!"#"0. "!
4#4"!
"#&"2
  &  &&        
3*&$.?@&
!"#"  0.          
#"&!( &=&&##"
&&*
051 0
0
2
4
6
8
1 0
1 2
0
2
4
6
8
1 0
2 0
3 2
7
E a s t [k m ]
1 9
2 4
1 1
8
1
N o r t h [ k m ]
2 8
H e i g h t [ k m ]
r a d i o s o n d e
Fig. 2 <=&! # 4#4" 
0.!!"&23B
$""!
Fig. 3 (# .6 "&! $ 
.?@  &  $    &      
"  2"  $"  3    .?@  &  $
($(,2$"
3.?@&$
#.6""2"
3
E"&!$.?@&
$&&$0.$
  &  2(  "  (3    $
#
2.6&=&&(#HF3*
  .?@  &! #" 
  #"  &      "  $  
&"*
           &  $
 #$ " &# (! 
!"#"  !  #    &!  2**    
4"(4#43  !( #
"      4&  #"  "  $
0.  #&(!"&
#&&*
ANALYSIS OF THE TEMPORAL AND SPATIAL
VARIABILITY OF WATER VAPOR
  .?@&$'>!
$CH1D!"""(!
&!*  $# #    #J   
!& $&  # !
!"  !            !
"  #    $(  #    &  $
&  #  (&  *    (&    "
      #    #  (#      !
#"#(!"$
    !"  &            #
&&*E =&!#.?@
&!!$&
(!  ($  "  28  "$  ,3*
E"  (        $    &&  2"
"!    $  *  "&    &  #  3*  
&!"(&#$#"*
    !      (  
 ,*- &&  (  
2 #!#  
&""3*'!"
"  #    (!  $"  &!"
(&      "  !  "  #  
&.?@""($
 2**I,&3"$ #$
=!#"* ?   (! ($
(2**&&.?@3
  &&    !(    (&  
!""*
#(!#""$
0.    "  $  #  (  $   ""
!&!($"
    =!"  #&  &!"  $"*  
 # $"     $ & #
""$&((&
!"        (    $(  2#
!!=&$ !"#" !43 #  !" 
"#"##"(#"C,
D*  #    ;  (  (!    ""
&    &!    =  &(+  &
$ 4&     
"$    #"(  #  (    $  CD*
 & $ $( #(
  $  #&  2@;K3  $      $
(#        "  #  0.  !!"  
C -D*#!&!($
#  '>        $  &  #  !  
&!"#"*&!"#"
"!  ! " #"  +
!  #  #  #J  &!  #"  
" $ ! !   &( 
($CD*
Fig. 4 =&!# .?@&! !$2#3!(&!2!!"3
(&2"3B'>"!$
 K! #$("#"
  !"      #4;  &    
!&      !$    #  &
"""# &!"$"" 
&# #" ##"( #
!!"#$"2**#
("3(!*
$!$"($
#&!" $" !& C8D*  
  !    !&  "&!  $  
"#" $ #&  '>  
$(      #4;  &B  
""  #  $"      "  "    
($&$"&
#!!*
 E- 8  ! &!"
#"  $  #&    :?/  &    
!"#,  '> $(
"" ! #, #& J,,< 
J,,<'7#-"$,*#4;
&&"!&
>$#$( "#"J
"  "  #  #"( Cn L * G,4F &4A
##"(    #      !! h L    &
 23 "  L L,,, &*  E 8
" "! !
  *-&A #&"&! $!
&!"#"2&#
  !      #   &!  #"
 x =3*&"#&
!$"*
Fig. 5 !"#"23"&!#
    $            , 
$(B  -A  2  3    A  24 3
!      !      #"B      "
"&"  #  #4;
&
      &  $    $(
"  #"      #4;  &*   
!" 4& #"  "
&"#" &""
&(!"&2**
$!!=&3#-A4!*
  $(  &!  "  #"  #  
-A4!$(#&,$,&
# &  "!  - &  1,, &
!"($A4!
$ 2$,&3"
2!3*$("#"
!!    $  "        $  $
#;**&(+-A$(#
!  "  MM h 2##"(    #    
!!&#&"
#    &3  "  4&  $
!"      A  $(  #  !  "  NN h
$!""$"
4&  C-D*           
$(#&-AA !  !!
&   &B  $#
(*   " #  $  
"!$,&=!&&$
"  $    #  #  !!=&    
( ( !# &B( &!
###!#""
  # $!"" &
&#($#(!"
&(($(*
Fig. 6 &!"#" "&!#
,$(B-A
2  3    A  24  3  !    
!      #"B      "  "  
&"##4;&
!"#-!#&
$,""J.?@
  "      !  #  $    &
!"(#
*    !"  #    & "
 !  "" CFD
#   -   "" !( $
7/*    $"  #    "" !  
&.?@&(&$(
"  & & $ , ""
4#5""2EF3*?
("$"&!&!
"  #"      &        
!(=!&2-"$#& <  <
'73 $ !"  #-  - 
""2E H3* < =!" &!"
#"#" &   "&! $
,    !"  #  &       ,  *  
!(      #&  $    
#5""$(-!"J#
&$$,,"!
! " # - &  - & !"( 
&! "#"  #-A4!
$(B#&$
#2!3*
Fig. 7 7&!$.?@&$
, $(  ,  "" 2$" 
3-$(, ""2&
 3  -  $(  - 
""2&"3
Fig. 8 &!"#" "&!#
-$(B-A
2  3    A  24  3  !    
!      #"B      "  "  
&"##4;&
CONCLUSIONS
(!#!
  &!  ($  #    (!  "  $  
06$4...2,-3*
!"!$(!2.?@3#""
$(#2$,G8&3
  #      #  &  #    &&*  0"
# !$# .?@&
$    ! "
&&*#!
  &!  #"  #   (!  $  &  #
"#"" "
  #4;  ""  &  #  &!"
$"$  &( * $(
&!"#"#&#&$
, "! "#=!&
!!"#&$-&
,&*"#4#5"#"$
& # - !" 5 #- 
""(""!*
ACKNOWLEDGMENTS
 !>"!!$ " ##
!&!"!($O*
!!  $  $A(($  ""  #  
  "  <!$    =&  ?
7 2<3" # 0$ 7#
=""!&  '(  O*
? "%#
!&=!&*?
""")!
"  <"  24)<3      6
#7&&" "2673#
(&"(&*
REFERENCES
CD  K(  *  K  *  7  *  %  *
<  *  "  7*  ?  *  0.  J
!!  :  ?  /    ."!$  ?
)#<!!F14H811 *
CD  6  <**  0$  &!!  #"  #  
&!        (  )  #
0!"",FI 8118*
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0!"";,,8*
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# 06"(* )# / "
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QRSTUVWXYZ[\ YX]YQ[RZT^_ \ `abbXRZ^\cdTedUZfaX_\ghijgk_ \ glm
 1F*
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0-H 848818*
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&$*."#'<"&#""
,114,1 *
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&&*/(618*
CD  ?  <*/*  "&"  "
@&    0&"  !"*  7&$  '(
.7&$,,*
CD  #  *6*  ;  0**    ##"  #  
&"    !!      #&"
&&*""23-48-1HF*
C D?&*K"*E.*
#&J  !!"    0.  &  
&!"  # #&"  "  !  
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F,-IF,8F11H*
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<("!"" F8H481,,*
C8D6* /( )*;* % ** ' 4
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!&$,,HH--4H8*
... Existing networks (not specifically designed for meteorological purposes) and specifically designed dense GNSS networks have been used for monitoring the distribution of water vapor in the atmosphere, with particular reference to its lower layer, that is, the troposphere. At least three different approaches have been applied: (1) investigation of the vertical column over a single station (Rocken et al. 1997), (2) exploitation of existing national GNSS networks (Seko et al. 2007;Inoue and Inoue 2007), and (3) implementation of specifically designed dense and hyperdense GNSS networks (Zhang et al. 2008;Realini et al. 2012;Sato et al. 2013;Tsuda et al. 2013;Oigawa et al. 2015). In all aforementioned studies, which are surely not exhaustive, the water vapor content was monitored to support weather forecasting, which is useful for interpreting severe meteorological events. ...
... Zhang et al. (2008) designed a mixed singleand double-frequency GNSS network with ~ 5-to 10-km spacing between the stations to support the weather forecasting in the metropolitan area of Beijing (China). Realini et al. (2012) and Sato et al. (2013) installed a network of 17 dual-frequency GNSS stations, specifically designed for high-resolution PWV measurements. The network has a horizontal spacing of 1-2 km, covers an area of approximately 10 × 6 km 2 , and is located near the Uji Campus of Kyoto University (Japan). ...
... • characterization of the temporal and spatial PWV variability at a local scale using 2D maps of GNSSderived PWV (Realini et al. 2012); ...
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This study presents an innovative procedure to monitor the precipitable water vapor (PWV) content of a wide and orographically complex area with low-density networks. The procedure, termed G4M (global navigation satellite system, GNSS, for Meteorology), has been developed in a geographic information system (GIS) environment using the free and open source GRASS GIS software (https://grass.osgeo.org). The G4M input data are zenith total delay estimates obtained from GNSS permanent stations network adjustment and pressure (P) and temperature (T) observations using existing infrastructure networks with different geographic distributions in the study area. In spite of the wide sensor distribution, the procedure produces 2D maps with high spatiotemporal resolution (up to 250 m and 6 min) based on a simplified mathematical model including data interpolation, which was conceived by the authors to describe the atmosphere’s physics. In addition to PWV maps, the procedure provides ∆PWV and heterogeneity index maps: the former represents PWV variations with respect to a “calm” moment, which are useful for monitoring the PWV evolution; and the latter are promising indicators to localize severe meteorological events in time and space. This innovative procedure is compared with meteorological simulations in this paper; in addition, an application to a severe event that occurred in Genoa (Italy) is presented.
... ing regional GNSS networks with resolutions lower than 10 km. Seko et al. (2004) employed 75 GPS receivers within an area of 20 × 20 km 2 around Tsukuba, Japan and analyzed the thickening of the humid boundary layer before the generation of a thunderstorm by using a tomography method and GNSS derived slant path delay (SPD) data (Shoji et al. 2004). Realini et al. (2012) and Sato et al. (2013) installed 17 GNSS stations with a horizontal spacing of 1−2 km near Uji campus of Kyoto University, which is located south of Kyoto prefecture, Japan. They succeeded to improve the horizontal resolution of the retrieved PWV maps by analyzing PWV from high elevation SPDs. However, it is difficult to understand physical ...
... Temporal variations of GNSS-derived PWV and surface rainfall amounts derived from a rain gauge associated with the passage of the precipitation cell were observed at the Uji campus (Fig. 2). PWV data used here was derived from the GNSS receiver at the Uji campus, which is one of the receivers of the hyper-dense GNSS network used by the authors in earlier studies (Realini et al. 2012; Sato et al. 2013). Precipitation intensity at the GNSS station rapidly increased from 2010 LST on 13 August, 2012, reached a maximum of more than 60 mm h −1 within a few minutes, and diminished by 2020 LST. ...
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Water vapor variations associated with a meso-γ scale convection were investigated using GNSS (Global Navigation Satellite System) derived PWV (precipitable water vapor) and high resolution numerical model data with a 250 m horizontal grid interval. A rapid increase of GNSS-derived PWV that occurred prior to the initiation of surface rainfall was well simulated by the numerical model. In the model, PWV values began to increase 16 min before the rainfall occurred at the surface. A local maximum of PWV was formed because of the generation of shallow free convection and surface water vapor flux convergence due to a lifting of an air parcel at approximately 1 km elevation by a preceding surface wind convergence. Due to the existence of a stable inversion layer between 2.2 and 3.5 km elevation, the shallow free convection took 11 min to rise above the inversion layer to form a deep convection. These results suggest that observation of local distributions of GNSS-derived PWV is useful for monitoring the generation of deep moist convection.
... Usually, high-accuracy ZTDs can be derived with the double difference (DD) method, where some common error sources are removed. Additionally, ZTDs can be estimated with precise point positioning (PPP) [9,[40][41][42][43][44][45][46][47]. ...
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... Here, it is noted that variations of the tropospheric measures can reach a standard deviation of 0.3-0.5 cm [65,66] which cannot be ignored in X-band systems. This conclusion seems to be mismatched with the one here, but actually it is just a verification of our research from another aspect. ...
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