On Jul 8, 2020, at 8:19 AM, Philip <herd_dog at cox.net> wrote:
Thanks again for confirming that the wgrib2 software loaded correctly. I
have been making good progress finding variables related to low level
winds such as the HGT series that, as you know, converts millibars to
altitude MSL.
The next step is to look at Rapid Refresh (RAP). Can you direct me to
someplace that has the names of the forecast models - equivalent to
gfs_0p50 for the Global Forecast System?
Thanks.
-----Original Message----- From: Roy Mendelssohn - NOAA Federal
Sent: Monday, July 6, 2020 6:35 PM
To: Philip
Subject: Re: [R] National Weather Service Data
Skimming the docs seems to assume a lot of knowledge of the data. The
best I can see there are two temperature variables:
tmpsfc (surface air temperature, K)
tmp2m (air temperature at 2m, K)
and one relative humidity:
rh2m (relative humidity at 2m, %)
Depending on what you are after, you might find it easier to use the UAF
ERDDAP server
(https://upwell.pfeg.noaa.gov/erddap/griddap/ncep_global.html) and
'rerddap' to get the data. 'rerddap' will read in the data into a nice
tibble, I also think the documentation is clearer with some nice
vignettes and the ability to get info about the data. For example the
command
rerddap::info('ncep_global')
<ERDDAP info> ncep_global
Base URL: https://upwell.pfeg.noaa.gov/erddap/
Dimensions (range):
time: (2011-05-06T12:00:00Z, 2020-07-08T12:00:00Z)
latitude: (-90.0, 90.0)
longitude: (0.0, 359.5)
Variables:
dlwrfsfc:
Units: W m-2
dswrfsfc:
Units: W m-2
pratesfc:
Units: kg m-2 s-1
prmslmsl:
Units: Pa
rh2m:
Units: %
tmp2m:
Units: K
tmpsfc:
Units: K
ugrd10m:
Units: m s-1
vgrd10m:
Units: m s-1
which would have answered a lot of your questions. If you had saved that
command to a variable there would be a lot more information, that is
just the summary.
HTH,
-Roy
On Jul 6, 2020, at 5:47 PM, Philip <herd_dog at cox.net> wrote:
Thanks for getting back to me. It is good to know that I am on the right
track.
I understand now that the output byte location of the data in the grib2
file not the actual data which in this case would be the 2 am forecast
six hours into the future. Can you advise me which of the examples in
Dr. Bowman's rNOMADS documentation will get me the tem[perature and
relative humidity data?
Philip.
-----Original Message----- From: Roy Mendelssohn - NOAA Federal
Sent: Monday, July 6, 2020 10:43 AM
To: Philip
Cc: stephen sefick ; r-help
Subject: Re: [R] National Weather Service Data
Hi Philip:
Results look correct to me. This might help you:
https://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/default_inv.html
-Roy
On Jul 6, 2020, at 9:29 AM, Philip <herd_dog at cox.net> wrote:
I am trying to access National Weather Service forecasting data through
the rNOMADS package. I?m not sure if the Weather Service software ?
grib2 ? loaded correctly. Second, some of the examples in the rNOMADS
documentation seem to run correctly but I?m not sure what the output
means. Any anvise would be greatly appreciated.
1 - I tried to load the wgrib2 software from instructions in the
following website:
https://bovineaerospace.wordpress.com/2015/04/26/how-to-install-rnomads-with-grib-file-support-on-windows/
2 ? the instructions say that if it loaded correctly I should get a
laundry list similar to what is below from the command:
The list I get looks different. Below is the first 20 or so entries.
How can I check to see if the wgrib2 loaded correctly?
wgrib2 v0.1.9.9 9/2013 Wesley Ebisuzaki, Reinoud Bokhorst, Jaakko
Hyv??tti, Dusan Jovic, Kristian Nilssen, Karl Pfeiffer, Pablo Romero,
Manfred Schwarb, Arlindo da Silva, Niklas Sondell, Sergey Varlamov
-0xSec inv X Hex dump of section X (0..8)
-MM inv reference time MM
-N_ens inv number of ensemble members
-RT inv type of reference Time
-S inv simple inventory with minutes and seconds
(subject to change)
-Sec0 inv contents of section0
-Sec3 inv contents of section 3 (Grid Definition
Section)
-Sec4 inv Sec 4 values (Product definition section)
-Sec5 inv Sec 5 values (Data representation section)
-Sec6 inv show bit-map section
-Sec_len inv length of various grib sections
-T inv reference time YYYYMMDDHHMMSS
-V inv diagnostic output
-VT inv verf time = reference_time + forecast_time
(YYYYMMDDHHMMSS)
-YY inv reference time YYYY
3 ? As I said, some of the documentation examples work and for some I
get error messages. Below is an example of one that seemed to work but
I don?t understand the output.
#GribInfo - page 20
urlsOut <- CrawlModels(abbrev="gfs_0p50",depth=2)
ModelParameters <- ParseModelPage(urlsOut[2])#[1] is most recent model
MyPred <- ModelParameters$pred[grep("06$",ModelParameters$pred)]
Levels <- c("2_m_above_ground","800_mb")
Variables <- c("TMP","RH")
GribInfo <- GribGrab(urlsOut[2],MyPred,Levels,Variables)
GribInv <- GribInfo(GribInfo[[1]]$file.name,"grib2")
The command GribInv$inventory returns:
$inventory
[1] "1:0:d=2020070606:TMP:800 mb:6 hour fcst:"
"2:148450:d=2020070606:RH:800 mb:6 hour fcst:"
[3] "3:414132:d=2020070606:TMP:2 m above ground:6 hour fcst:"
"4:571266:d=2020070606:RH:2 m above ground:6 hour fcst:"
This is supposed to be temperature and relative humidity 2 meters above
the ground and at 800 milibars for 2020 ? July 6 ? at ZULU time 0600.
But I have no idea what the numbers 414132 ? second line ? mean.
Any advise would be greatly appreciated.
Philip Heinrich
From: stephen sefick
Sent: Thursday, July 2, 2020 3:20 PM
To: Philip
Cc: r-help
Subject: Re: [R] National Weather Service Data
I am unfamiliar with Rnomads. Could you provide a minimal reproducable
example? You are more likely to receive help this way.
On Thu, Jul 2, 2020, 18:06 Philip <herd_dog at cox.net> wrote:
Is anyone out there familiar with rNOMADS? It is a package to get into
National Weather Service forecasting data with R?
I'm not sure the Weather Service software named wgrib2 loaded correctly
because some of the stuff won't run and I can't make much sense out of
some of the output.
Thanks.
[[alternative HTML version deleted]]