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href="#HIRS"><span>HIRS</span></a></li><li><a class="tocitem" href="#MHS"><span>MHS</span></a></li></ul></li></ul></li><li><a class="tocitem" href="../full_api/">Full API</a></li></ul><div class="docs-version-selector field has-addons"><div class="control"><span class="docs-label button is-static is-size-7">Version</span></div><div class="docs-selector control is-expanded"><div class="select is-fullwidth is-size-7"><select id="documenter-version-selector"></select></div></div></div></nav><div class="docs-main"><header class="docs-navbar"><a class="docs-sidebar-button docs-navbar-link fa-solid fa-bars is-hidden-desktop" id="documenter-sidebar-button" href="#"></a><nav class="breadcrumb"><ul class="is-hidden-mobile"><li><a class="is-disabled">Examples</a></li><li class="is-active"><a href>ATOVS (AMSU-A, HIRS, MHS)</a></li></ul><ul class="is-hidden-tablet"><li class="is-active"><a href>ATOVS (AMSU-A, HIRS, MHS)</a></li></ul></nav><div class="docs-right"><a class="docs-navbar-link" href="https://github.com/eumetsat/MetopDatasets.jl" title="View the repository on GitHub"><span class="docs-icon fa-brands"></span><span class="docs-label is-hidden-touch">GitHub</span></a><a class="docs-navbar-link" href="https://github.com/eumetsat/MetopDatasets.jl/blob/main/docs/src/ATOVS.md" title="Edit source on GitHub"><span class="docs-icon fa-solid"></span></a><a class="docs-settings-button docs-navbar-link fa-solid fa-gear" id="documenter-settings-button" href="#" title="Settings"></a><a class="docs-article-toggle-button fa-solid fa-chevron-up" id="documenter-article-toggle-button" href="javascript:;" title="Collapse all docstrings"></a></div></header><article class="content" id="documenter-page"><h2 id="ATOVS"><a class="docs-heading-anchor" href="#ATOVS">ATOVS</a><a id="ATOVS-1"></a><a class="docs-heading-anchor-permalink" href="#ATOVS" title="Permalink"></a></h2><p>Advanced TIROS Operational Sounder (ATOVS) is a sounding instrument package. The ATOVS instruments have both been flown on NOAA satellites and on the METOP satellites. The METOP ATOVS instrument package consists of 3 sensors:</p><ul><li>Advanced Microwave Sounding Units A (AMSU-A)</li><li>High Resolution InfraRed Sounder (HIRS)</li><li>Microwave Humidity Sounder (MHS)</li></ul><p>For more information see <a href="https://user.eumetsat.int/s3/eup-strapi-media/pdf_atovsl1b_pg_8bbaa8ba48.pdf">ATOVS Level 1b Product Guide</a></p><h2 id="AMSU-A"><a class="docs-heading-anchor" href="#AMSU-A">AMSU-A</a><a id="AMSU-A-1"></a><a class="docs-heading-anchor-permalink" href="#AMSU-A" title="Permalink"></a></h2><p>The Advanced Microwave Sounding Unit-A (AMSU-A) is an instrument on the METOP satellites. AMSU-A is a microwave radiometer with 15 channels and is one of the three ATOVS sensors.</p><p>The AMSU-A L1B products contain the radiance measured at all 15 channels. See the <a href="https://data.eumetsat.int/product/EO:EUM:DAT:METOP:AMSUL1">AMSU-A Level 1B product pagel</a> for more information. The frequency of each channel is given in <a href="https://web.archive.org/web/20060420075941/http://www2.ncdc.noaa.gov/docs/klm/html/c3/sec3-3.htm">NOAA KLM User's Guide</a></p><p>This example is made using the following packages.</p><pre><code class="nohighlight hljs">[13f3f980] CairoMakie v0.15.6 |
| 3 | +[db073c08] GeoMakie v0.7.15</code></pre><pre><code class="language-julia hljs">using MetopDatasets |
| 4 | +using CairoMakie, GeoMakie, Statistics |
| 5 | + |
| 6 | +# Open the dataset. |
| 7 | +path = "AMSA_xxx_1B_M03_20250915221320Z_20250915235520Z_N_O_20250915235036Z.nat" |
| 8 | +ds = MetopDataset(path, maskingvalue=NaN); |
| 9 | + |
| 10 | +# read location |
| 11 | +latitude = ds["earth_location"][1,:,:] |
| 12 | +longitude = ds["earth_location"][2,:,:] |
| 13 | + |
| 14 | +# read radiance |
| 15 | +radiance_of_band = ds["scene_radiance"][2,:,:] # Channel 2 is 31.4 GHz |
| 16 | + |
| 17 | +radiance_q05 = quantile(radiance_of_band[:],0.05) |
| 18 | +radiance_q90 = quantile(radiance_of_band[:],0.90) |
| 19 | + |
| 20 | +fig = let |
| 21 | + # Create figure and axis |
| 22 | + fig = Figure() |
| 23 | + ax = GeoAxis(fig[1, 1], |
| 24 | + title = "AMSU", |
| 25 | + xlabel = "longitude", |
| 26 | + ylabel = "latitude") |
| 27 | + |
| 28 | + # plot data with color map |
| 29 | + scatter!(ax, longitude[:], latitude[:], |
| 30 | + color = radiance_of_band[:], colorrange = (radiance_q05,radiance_q90), markersize = 2) |
| 31 | + |
| 32 | + # Add colorbar |
| 33 | + Colorbar(fig[1,2], colorrange = (radiance_q05,radiance_q90) , label="mW/m2/sr/cm-1") |
| 34 | + |
| 35 | + # Add coastlines |
| 36 | + lines!(ax, GeoMakie.coastlines()) |
| 37 | + fig |
| 38 | +end</code></pre><p><img src="../AMSU_A_channel_2_plot.png" alt="AMSU-A channel 2"/> The plot shows the radiance for the AMSU-A channel 2 (31.4 GHz) observed during an orbit.</p><h2 id="HIRS"><a class="docs-heading-anchor" href="#HIRS">HIRS</a><a id="HIRS-1"></a><a class="docs-heading-anchor-permalink" href="#HIRS" title="Permalink"></a></h2><p>The High Resolution Infrared Sounder (HIRS) is an instrument on the METOP satellites. It is a 20 channel infrared sounder and one of the three Advanced TIROS Operational Sounder (ATOVS) sensors. </p><p>The level 1B HIRS files contain the radiance of the 19 channels and the reflectance for channel 20. See the <a href="https://data.eumetsat.int/product/EO:EUM:DAT:MULT:HIRSL1">HIRS Level 1B product page</a> for more information. This example shows how we plot the radiance from channel 7 on a map.</p><p>This example is made using the following packages.</p><pre><code class="nohighlight hljs">[13f3f980] CairoMakie v0.15.6 |
| 39 | +[db073c08] GeoMakie v0.7.15</code></pre><pre><code class="language-julia hljs">using MetopDatasets |
| 40 | +using CairoMakie, GeoMakie, Statistics |
| 41 | + |
| 42 | +# Open the dataset. |
| 43 | +path = "HIRS_xxx_1B_M01_20160720074253Z_20160720092153Z_N_O_20160720083048Z.nat" |
| 44 | +ds = MetopDataset(path, maskingvalue=NaN); |
| 45 | + |
| 46 | +# read location |
| 47 | +latitude = ds["earth_location"][1,:,:] |
| 48 | +longitude = ds["earth_location"][2,:,:] |
| 49 | + |
| 50 | +# read radiance |
| 51 | +radiance_of_band = ds["digital_a_rad"][7,:,:] # Channel 7 |
| 52 | + |
| 53 | +radiance_q05 = quantile(radiance_of_band[.!isnan.(radiance_of_band)],0.05) |
| 54 | +radiance_q95 = quantile(radiance_of_band[.!isnan.(radiance_of_band)],0.95) |
| 55 | + |
| 56 | +fig = let |
| 57 | + # Create figure and axis |
| 58 | + fig = Figure() |
| 59 | + ax = GeoAxis(fig[1, 1], |
| 60 | + title = "HIRS Channel 7", |
| 61 | + xlabel = "longitude", |
| 62 | + ylabel = "latitude") |
| 63 | + |
| 64 | + # plot data with color map |
| 65 | + scatter!(ax, longitude[:], latitude[:], |
| 66 | + color = radiance_of_band[:], colorrange = (radiance_q05,radiance_q95), markersize = 2) |
| 67 | + |
| 68 | + # Add colorbar |
| 69 | + Colorbar(fig[1,2], colorrange = (radiance_q05,radiance_q95)) |
| 70 | + |
| 71 | + # Add coastlines |
| 72 | + lines!(ax, GeoMakie.coastlines()) |
| 73 | + fig |
| 74 | +end</code></pre><p><img src="../HIRS_plot.png" alt="HIRS channel 7"/></p><h2 id="MHS"><a class="docs-heading-anchor" href="#MHS">MHS</a><a id="MHS-1"></a><a class="docs-heading-anchor-permalink" href="#MHS" title="Permalink"></a></h2><p>The Microwave Humidity Sounder (MHS) is an instrument on the METOP satellites. It measures the earth using 5 microwave channels sensitive to surface temperatures, emissivities, and atmospheric humidity. MHS is one of the three Advanced TIROS Operational Sounder (ATOVS) sensors.</p><p>The level 1B MHS files contain the radiance of the 5 channels. See the <a href="https://data.eumetsat.int/product/EO:EUM:DAT:METOP:MHSL1">MHS Level 1B product page</a> for more information. This example shows how we compute the brightness temperature of channel 3 and plot it on a map. Note that <code>scene_radiances</code> can also be plotted directly and this will result in a very similar image but with a different color range. </p><p>This example is made using the following packages.</p><pre><code class="nohighlight hljs">[13f3f980] CairoMakie v0.15.6 |
| 75 | +[db073c08] GeoMakie v0.7.15</code></pre><pre><code class="language-julia hljs"> |
| 76 | +using MetopDatasets |
| 77 | +using CairoMakie, GeoMakie, Statistics |
| 78 | + |
| 79 | +# Open the dataset. |
| 80 | +path = "MHSx_xxx_1B_M03_20250915084851Z_20250915103051Z_N_O_20250915102514Z.nat" |
| 81 | +ds = MetopDataset(path, maskingvalue=NaN); |
| 82 | + |
| 83 | +# select band to plot: 1,2,3,4 or 5 |
| 84 | +band_to_plot = 3 |
| 85 | + |
| 86 | +# read location |
| 87 | +latitude = ds["earth_location"][1,:,:] |
| 88 | +longitude = ds["earth_location"][2,:,:] |
| 89 | + |
| 90 | +# read radiance |
| 91 | +radiance_of_band = ds["scene_radiances"][band_to_plot,:,:] |
| 92 | + |
| 93 | +## convert radiance to brightness temperature. |
| 94 | + |
| 95 | +# get wave number of channel |
| 96 | +mhs_giadr = read_first_record(ds, MetopDatasets.GIADR_MHS_RADIANCE) |
| 97 | +wave_number_cm = get_scaled(mhs_giadr, "central_wavenumber_h$(band_to_plot)") |
| 98 | + |
| 99 | +# covert wave number from cm^-1 to m^-1 |
| 100 | +wave_number_SI = 10.0^2 * wave_number_cm |
| 101 | + |
| 102 | +# covert radiance from mW/m2/sr/cm-1 to W/m2/sr/m-1 |
| 103 | +radiance_SI = radiance_of_band * 10^(-5) |
| 104 | + |
| 105 | +T_brightness_uncorrected = brightness_temperature.(radiance_SI, wave_number_SI) |
| 106 | + |
| 107 | +# Apply linear corrections to the brightness temperature |
| 108 | +a_correction = get_scaled(mhs_giadr, "temperature_h$(band_to_plot)_intercept") |
| 109 | +b_correction = get_scaled(mhs_giadr, "temperature_h$(band_to_plot)_slope") |
| 110 | +T_brightness = a_correction .+ T_brightness_uncorrected .* b_correction |
| 111 | + |
| 112 | +# Plot the correct brightness temperature |
| 113 | +T_brightness_q05 = quantile(T_brightness[:],0.05) |
| 114 | +T_brightness_q95 = quantile(T_brightness[:],0.95) |
| 115 | + |
| 116 | +fig = let |
| 117 | + # Create figure and axis |
| 118 | + fig = Figure() |
| 119 | + ax = GeoAxis(fig[1, 1], |
| 120 | + title = "MHS band: H$(band_to_plot)", |
| 121 | + xlabel = "longitude", |
| 122 | + ylabel = "latitude") |
| 123 | + |
| 124 | + # plot data with color map |
| 125 | + scatter!(ax, longitude[:], latitude[:], |
| 126 | + color = T_brightness[:], colorrange = (T_brightness_q05,T_brightness_q95), markersize = 1) |
| 127 | + |
| 128 | + # Add colorbar |
| 129 | + Colorbar(fig[1,2], colorrange = (T_brightness_q05,T_brightness_q95), label="K") |
| 130 | + |
| 131 | + # Add coastlines |
| 132 | + lines!(ax, GeoMakie.coastlines()) |
| 133 | + fig |
| 134 | +end</code></pre><p><img src="../MHS_Tb_plot.png" alt="MHS Brightness temperature"/> The plot shows the brightness temperature for the MHS H3 channel (183.311 GHz) observed during an orbit.</p></article><nav class="docs-footer"><a class="docs-footer-prevpage" href="../IASI/">« IASI</a><a class="docs-footer-nextpage" href="../full_api/">Full API »</a><div class="flexbox-break"></div><p class="footer-message">Powered by <a href="https://github.com/JuliaDocs/Documenter.jl">Documenter.jl</a> and the <a href="https://julialang.org/">Julia Programming Language</a>.</p></nav></div><div class="modal" id="documenter-settings"><div class="modal-background"></div><div class="modal-card"><header class="modal-card-head"><p class="modal-card-title">Settings</p><button class="delete"></button></header><section class="modal-card-body"><p><label class="label">Theme</label><div class="select"><select id="documenter-themepicker"><option value="auto">Automatic (OS)</option><option value="documenter-light">documenter-light</option><option value="documenter-dark">documenter-dark</option><option value="catppuccin-latte">catppuccin-latte</option><option value="catppuccin-frappe">catppuccin-frappe</option><option value="catppuccin-macchiato">catppuccin-macchiato</option><option value="catppuccin-mocha">catppuccin-mocha</option></select></div></p><hr/><p>This document was generated with <a href="https://github.com/JuliaDocs/Documenter.jl">Documenter.jl</a> version 1.14.1 on <span class="colophon-date" title="Wednesday 24 September 2025 12:25">Wednesday 24 September 2025</span>. Using Julia version 1.11.7.</p></section><footer class="modal-card-foot"></footer></div></div></div></body></html> |
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