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Linux Basics
The average student has limited experience with the Linux operating system.
However, most research in the atmospheric sciences is conducted in Linux. Here
are some help pages that can help get anyone started and even answers questions
for the experienced user
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Really Linux offers a nice online help guide for the Linux
beginner.
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Consult the online
Linux man pages. The man (refers to “manual”) page provides
an electronic documentation of how to use the numerous commands
at the command prompt. I regularly use this feature.
Data Sources
Tropical Cyclones:
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The
NOAA Hurricane Research Division has flight-level,
radar, and dropsonde data as well as surface wind analyses for
most Atlantic basin tropical systems since 1994. The data is
free (but a sign-in is required)
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The
Naval Research Lab (NRL) provides a free and extensive
archive of satellite imagery for most global TCs (and all
Atlantic TCs) since 1997. Storm-relative images and movies can
be obtained for products from GOES, TRMM, SSMI, AMSU, MODIS,
CloudSat, and WindSat (and many more). This is an excellent
site for quick-look data.
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The
NOAA Tropical Prediction Center/National Hurricane Center
maintains a free archive of operational forecasts, discussions,
storm reports, and “best track” data for each Atlantic and east
Pacific TC. This is an excellent site for quick looks at storm
history, evolution, and impacts.
Radar Data:
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NCDC offers free access to the archived NEXRAD
(WSR-88D)
Level-II and
Level-III data from most radar sites. Data can be obtained
via NCDC's
HDSS access system. The data is delivered via FTP in short
order, and can be read in by several of the software programs
listed below. Data go back as far as 1991 for some sites, and is
available for most sites for the past 10 years. These are the
actual radar volumes collected by each radar in real time (they
only become available online after about 2-4 weeks later). Good
for detailed radar analyses.
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National 2 km radar reflectivity composites from GHRC: The
composites are taken from the operating network of radars over
the US. The data comprise the maximum reflectivity from any
nearby radar over a 15-minute period. There are no velocity data
included. The data are in HDF format (we can acquire some
programs to read it), in 15 minute intervals, and the
reflectivity is binned in 5 dBZ increments. Because of its
national coverage and smaller file sizes, this dataset is
optimal for viewing the mesoscale structure of a system that may
span multiple radars, and is good for viewing large time series
of data over a region (e.g. if you're looking for a case study).
Data ordered on line and delivered by FTP.
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NCDC also offers free access to the archived NEXRAD
National Mosaic Reflectivity Images. This site makes for a
good quick-look survey of national radar data. These
images go back through 1995, and are available on an hourly
basis from 1997 onward. This site is essentially a gif image
server for the archived data. Other sources are better for
detailed research analysis.
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Plymouth State Weather Center offers a free archive for the
most recent 15 days single-site NIDS archives for the most
recent 15 days.
Satellite Data:
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Wisconsin's Space Science and Engineering Center archive is
an excellent source for GOES iamgery. The data can be ordered
online, and are delivered by FTP. You can order any or all of
the 5 standard channels, and can specify a limited domain for
the data in order to save on file size. Data delivery can take
2-4 weeks, so this is not a speedy way to get a quick look at
data. Data in the McIDAS AREA format can be plotted with the
McIDAS-Lite software (see below)
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The
Naval Research Lab (NRL) provides a free and extensive
archive of satellite imagery for most global TCs (and all
Atlantic TCs) since 1997. Storm-relative images and movies can
be obtained for products from GOES, TRMM, SSMI, AMSU, MODIS,
CloudSat, and WindSat (and many more). This is an excellent
site for quick-look TC data.
Quick Look Case Study Imagery:
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Plymouth State offers a "Make your own" product generator
from archived data. You can interactively plot surface data,
upper air data, and raob data. This site also includes access to
the NCEP global reanalysis dataset. You can't necessarily
extract actual data, but you can make a tremendous variety of
plots, and the archives go back quite far.
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SPC’s archive of Severe Weather events provides a synopsis
of many fields and parameters most frequently found to be
associated with severe thunderstorms. Products include constant
pressure level plots, computed diagnostic fields, Skew-Ts,
profiler plots, and radar, satellite, and lightning imagery as
well as a brief narrative evaluation of the synoptic situation
for each day that any severe weather occurred. The number of
products available for each events has increased in recent
years.
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NCAR's MMM online image archive: warm season data plots from
the Plains are archived. Includes radar, wind profiler,
satellite, upper air, surface, sounding, and model images. Data
availability is fairly good, and this is an excellent way to
identify potential case studies and overview the data (before
ordering the full datasets from the sites below). Some of the
data go back as far as 1997.
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SPC's archive of operational mesoanalysis images.
Forecasters use these in real-time to maintain situational
awareness and monitor derived real-time parameters such as 0-6
km shear, storm-relative helicity, and mixed-layer CAPE. Useful
in retrospective cases analyses. Only the national sector images
from May 2005 onward are archived: they're coarse, but they are
really the only thing of their kind online right now.
Gridded Analyses and
Reanalysis Data:
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NOMADS Web Interface Model Data Archive provides access to
the model data repository at NCDC. This repository contains both
archived and on-line model data. You can access the on-line data
using traditional access methods (web-based or ftp), or you can
use open and distributed access methods... With the NOMADS Web
Interface you can create, display, and download plots, use ftp
to download parameters and files, and use the NOMADS Distributed
Data Server using DODS/OPeNDAP and the GrADS-DODS/OPeNDAP Server
(GDS) to access the data directly from your preferred client or
desktop. You can also perform remote calculations using scripts
under the GDS." The RUC, Meso-ETA, and GFS (AVN/MRF) model data
are all available through this excellent interface. It is good
for both quick looks at data (online plotting) and for more
detailed analysis (downloading the data for use in local
software).
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ECMWF Climatology viewer: monthly 2.5x2.5 degree global data
from 10--1000 mb, extending from Jan 1985-Dec 1992. You can
interactively plot and download geopotential, surface height,
surface pressure, specific humidity, temperature at 2m, zonal
velocity, and meridional velocity. Good for looking at long-term
averages.
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NOAA CDC Interactive Plotting webpage: Extensive means to
plot global averaged and climatological data in a variety of
formats. Raw data can be obtained. Useful for looking at
long-term averages
Software
Dr. Eastin has most of the following
software/code on his machine. Most (if not all) of the software
should also be installed/available on your machine. This list is
designed to save time when trying to tackle the same problems that I
or other students have already tackled. If you develop or discovered
something new, please pass it on for all to utilize.
Making Figures:
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Gnuplot (freeware, Linux): Excellent tool to create PS and EPS
figures from ASCII data organized in a columnar format. Dr.
Eastin regularly uses this to make many of my plots for
conference presentations and papers. An
online manual is available.
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GrADS (freeware, Linux): Excellent tool to create, PS, EPS,
GIF, and JPG figures from gridded data in unformatted,
sequential, binary format (e.g. output from C and/or FORTRAN
programs). GrADS can also read
other special formats (GRIB, HDF, and
NetCDF) of gridded data. GrADS
can also read station data (surface data, soundings, etc.) in
its special format. There are a handful of canned FORTRAN
programs available online to read in specific kinds of data and
write them back out to GrADS
format. GrADS is
interactive/command-line based, and requires some basic
programming for optimal use. It makes standard 2D plots, over
which user has a high degree of control.
GrADS requires a “control” (.ctl)
file to describe the contents of the data file. Dr. Eastin
regularly uses this software. Significant
online help is available.
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Xfig (freeware, Linux): Excellent tool to import and modify
existing figures of almost any format (JPEG, GIF, EPS, PS, TIFF,
etc,). You can also create your own figures (such as diagrams
of conceptual models) from scratch. Dr. Eastin regularly use
this software to make and modify figures. An
online manual is available.
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Gimp (freeware, Linux): Also an excellent software package to
create and modify figures of almost any format. Dr. Eastin uses
this occasionally, but it can be very powerful for certain
applications. An
online manual is available.
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NCL (freeware, Linux): Reads in gridded
data in many different formats. NCL can read in almost any
ASCII-formatted table-like dataset if you tell it the ordering
of the variables. There are a very large number of canned
scripts online for NCL that make it fairly easy to quickly
produce an attractive plot. NCL is script/compiler based
(non-interactive), and can produce a wide variety of plot
types. Dr. Eastin has not used this software, and it is not
pre-installed on your machine, but others have indicated that it
is very powerful.
Radar Data Analysis and Plotting:
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SOLO II (freeware, Linux):
This is the ultimate radar analysis tool for NOAA P-3 radar data
(and can be used for Level-II NEXRAD data). SOLO II is a
widget-driven, interactive program that displays sweeps of the
radar data and enables the user to edit (i.e. unfold) the
velocity data, correct or delete bad data points, and to compare
data from different times or different fields on the same
screen, using windows whose plotting coordinates are linked to
one another. The best way to ensure that your velocity data are
properly unfolded is to do it by hand using the editor
function. Dr. Eastin has extensive experience working with the
NOAA P-3 radar data and has several canned routines that can be
used. SOLO II has a good deal of information in its many help
menus. Dr. Eastin has distilled this into an
informal manual (see him for copy). There is only
minimal help/information available via the web.
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GRLevel2 Analyst (licensed, Windows): Uses Level-II NEXRAD
radar data that has already been downloaded to a local machine.
You can view radar reflectivity, velocity, and spectral width
fields using an interactive GUI that allows the user to move
through the elevations in a volume scan, make cross sections and
produce 3-D views. Some parameters are also computed from the
Level-II data including: vertically integrated liquid (VIL),
echo tops (ET), rotational velocity, and mesocyclone detection.
An excellent tool for basic analysis of storm characteristics.
Dr. Eastin uses this software regularly.
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NCDC Java Nexrad Viewer and Data Exporter (freeware, Linux
and Windows): Loads Level-II and Level-III NEXRAD radar data
into applications that are launched via Java Web Start and run
on your local machine while accessing the data remotely from the
archive at the NCDC. The Java Nexrad Viewer provides tools for
custom data overlays, animations and basic queries. The export
of images and movies is provided in multiple formats, including
GrADS. Dr. Eastin uses this software regularly
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GrADS
(freeware, Linux): 2 km national composite reflectivity data
from GHRC can be converted to GrADS
format using available FORTRAN code. In
GrADS, you can plot the
reflectivities, and then overlay with other
meteorological data. Dr. Eastin has not used this aspect of
GrADS before. Significant
online help is available.
Satellite Data
Plotting:
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McIDAS Lite (freeware, Linux): This package is an
interactive, widget-driven, stripped-down version of
McIDAS that can be used to GOES
satellite data in McIDAS AREA format
from Wisconsin’s SSEC archive (see above). Somewhat limited,
but good enough to review data and make simple plots. Dr.
Eastin has not used this software, and it is not pre-installed
on your machine, but it comes highly recommended.
Sounding Data
Analysis and Plotting:
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capecalc.f (a C
program): Dr. Eastin has developed this program to reliably
calculate thermodynamic and kinematic parameters from sounding
data in ASCII format. The program expects to receive CLASS
format soundings. You can rewrite the read statements for other
formats, or Dr. Eastin has code that converts other sounding
formats to CLASS format.
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GrADS
(freeware, UNIX and Windows): A script is available online that
will plot a skew-T for gridded data
(e.g. a model grid point) provided that the vertical coordinate
is pressure. A script is also available to help you quickly
identify the pressure coordinates of Cartesian data. The skew-T
script also computes some thermodynamic indices, which are of
questionable reliability. Dr. Eastin has not used this
application in GrADS in quite some time. Significant
online help is available.
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NCL (freeware, Linux): NCL has a skew-T plotting program
that you can run with one of the NCL canned scripts that
exist. NCL also computes some thermodynamic indices, which
are of questionable quality. Dr. Eastin has not used this
software, but it comes highly recommended.
Surface Data Analysis
and Plotting:
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GrADS (freeware,
Linux): Code is available to convert ASCII-formatted surface
data into GrADS station files and
gridded data (via interpolation). GrADS
can plot the standard station model as well as several
modifications thereto, and can overlay the station data with any
other meteorological data that you have in
GrADS format. Dr. Eastin has limited experience with
this application, but extensive
online help is available.
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NCL (freeware, UNIX and maybe others): Although Dr. Eastin
has not used these before, there
appear to be numerous scripts online to plot surface data with
NCL.
Severe weather
Reports:
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Severe Plot (freeware, Windows): Comes with archived data
prepackaged and is useful for plotting historical storm reports.
Self contained and interactive/widget driven. Dr. Eastin has
not used this before, but it comes highly recommended.
Literature Search
Resources
The UNCC library has fairly good online resources
for obtaining most meteorological articles in PDF format.
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AMS Journals Online: Search all articles published in
American Meteorological Society journals. You can search by
title, keyword, author, or for a particular word within the full
text of the article. This is not necessarily a good way to
branch out a literature search, but it is a good way to get
started on a topic, or to find a paper whose reference
information you have forgotten. Free electronic versions of all
papers should be available. If not, you may need to go through
Academic Search Premier (see below) or use the online
Inter-Library Loan system
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Web of Science: Extremely powerful tool because not only can you search for
articles (including non-AMS articles), but you can also find every reference
that has cited the article since it has been published. Very helpful for
branching out a literature search and staying on top of the current knowledge in
a topic area. Access should be possible from any UNCC computer, or through the
UNCC Library login syste
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Academic Search Premier. Searchable database of academic
journals, including some meteorological journals. Access should
be possible from any UNCC computer, or through the UNCC Library
login system.
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Google Scholar. If you feel lucky, you can also check for
articles here. In some cases, full text may be available online.
Printing
You can print from any research
lab computer in the to the lab’s B/W printer (named “labhp”) using
standard GUI methods in either Linux or Windows. In Linux you can
also print from the command line using the commands:
lpr –Plabhp
filename [to print PS files]
enscript filename
[to print ASCII text files]
Check the man pages (see above)
more options with command line printing.
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