{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "## 02_Xarray: Plotting" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Overview\n", "1. Work with an Xarray `Dataset`\n", "2. Select a variable from the dataset\n", "3. Create a contour plot of gridded CFSR reanalysis data" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Imports" ] }, { "cell_type": "code", "execution_count": 1, "metadata": {}, "outputs": [], "source": [ "import xarray as xr\n", "import pandas as pd\n", "import numpy as np\n", "from metpy.units import units\n", "import metpy.calc as mpcalc\n", "import cartopy.crs as ccrs\n", "import cartopy.feature as cfeature\n", "import matplotlib.pyplot as plt" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Work with an Xarray `Dataset`" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "An Xarray [Dataset](http://xarray.pydata.org/en/stable/generated/xarray.Dataset.html) consists of one or more `DataArray`s. Let's continue to work with the CFSR NetCDF files from the previous notebook. " ] }, { "cell_type": "code", "execution_count": 2, "metadata": {}, "outputs": [], "source": [ "year = 1993\n", "ds_slp = xr.open_dataset(f'/cfsr/data/{year}/pmsl.{year}.0p5.anl.nc')\n", "ds_g = xr.open_dataset(f'/cfsr/data/{year}/g.{year}.0p5.anl.nc')" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "Examine the SLP dataset" ] }, { "cell_type": "code", "execution_count": 3, "metadata": {}, "outputs": [ { "data": { "text/html": [ "
<xarray.Dataset>\n", "Dimensions: (time: 1460, lat: 361, lon: 720)\n", "Coordinates:\n", " * time (time) datetime64[ns] 1993-01-01 ... 1993-12-31T18:00:00\n", " * lat (lat) float32 -90.0 -89.5 -89.0 -88.5 -88.0 ... 88.5 89.0 89.5 90.0\n", " * lon (lon) float32 -180.0 -179.5 -179.0 -178.5 ... 178.5 179.0 179.5\n", "Data variables:\n", " pmsl (time, lat, lon) float32 ...\n", "Attributes:\n", " description: pmsl as a single level variable\n", " year: 1993\n", " source: http://nomads.ncdc.noaa.gov/data.php?name=access#CFSR-data\n", " references: Saha, et. al., (2010)\n", " created_by: User: kgriffin\n", " creation_date: Wed Apr 4 05:59:11 UTC 2012
<xarray.DataArray 'pmsl' (time: 1460, lat: 361, lon: 720)>\n", "[379483200 values with dtype=float32]\n", "Coordinates:\n", " * time (time) datetime64[ns] 1993-01-01 ... 1993-12-31T18:00:00\n", " * lat (lat) float32 -90.0 -89.5 -89.0 -88.5 -88.0 ... 88.5 89.0 89.5 90.0\n", " * lon (lon) float32 -180.0 -179.5 -179.0 -178.5 ... 178.5 179.0 179.5\n", "Attributes:\n", " level_type: single level variable\n", " units: Pa\n", " long_name: pressure reduced mean sea level
<xarray.DataArray 'pmsl' (lat: 361, lon: 720)>\n", "[259920 values with dtype=float32]\n", "Coordinates:\n", " time datetime64[ns] 1993-03-14T18:00:00\n", " * lat (lat) float32 -90.0 -89.5 -89.0 -88.5 -88.0 ... 88.5 89.0 89.5 90.0\n", " * lon (lon) float32 -180.0 -179.5 -179.0 -178.5 ... 178.5 179.0 179.5\n", "Attributes:\n", " level_type: single level variable\n", " units: Pa\n", " long_name: pressure reduced mean sea level