<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "https://jats.nlm.nih.gov/nlm-dtd/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" specific-use="SMUR" dtd-version="3.0" xml:lang="en">
<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2025-4229</article-id>
<title-group>
<article-title>Meteorological Evaluation of the MERRA-2 Reanalysis Dataset: Insights for the Indian Subcontinent</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Malasani</surname>
<given-names>Chakradhar Reddy</given-names>
<ext-link>https://orcid.org/0000-0001-5126-0847</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Swain</surname>
<given-names>Basudev</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Patel</surname>
<given-names>Ankit</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Chandrasekharan</surname>
<given-names>Arundathi</given-names>
<ext-link>https://orcid.org/0009-0005-9888-5410</ext-link>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Singh</surname>
<given-names>Aishwarya</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Anchan</surname>
<given-names>Nidhi L.</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Song</surname>
<given-names>Rui</given-names>
</name>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Sharma</surname>
<given-names>Amit</given-names>
</name>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Gunthe</surname>
<given-names>Sachin S.</given-names>
<ext-link>https://orcid.org/0000-0002-7903-7783</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Centre for Atmospheric and Climate Sciences, Indian Institute of Technology Madras, Chennai, India</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Environmental Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Atmospheric, Oceanic and Planetary Physics, University of Oxford, U.K.</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Climate System Research Unit, Finnish Meteorological Institute, Finland</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Max Planck Institute for Chemistry, Biogeochemistry Department, Mainz, Germany</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>Department of Energy, Environmental, and Chemical Engineering, Washington University in Saint Louis, Missouri, USA</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>National Centre for Earth Observation, Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, OX1 3PU, UK</addr-line>
</aff>
<aff id="aff8">
<label>8</label>
<addr-line>Department of Civil and Infrastructure Engineering, Indian Institute of Technology Jodhpur, Jodhpur, India</addr-line>
</aff>
<pub-date pub-type="epub">
<day>02</day>
<month>12</month>
<year>2025</year>
</pub-date>
<volume>2025</volume>
<fpage>1</fpage>
<lpage>31</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2025 Chakradhar Reddy Malasani et al.</copyright-statement>
<copyright-year>2025</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4229/">This article is available from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4229/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4229/egusphere-2025-4229.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4229/egusphere-2025-4229.pdf</self-uri>
<abstract>
<p>MERRA-2 meteorological data is widely utilized across the Indian region to investigate various climatological phenomena, necessitating a thorough evaluation of its accuracy. This study evaluates the performance of MERRA-2 meteorological fields over the Indian region by combining radiosonde measurements with satellite observations from AIRS and TRMM, along with reanalysis data from NCEP/NCAR. Our analysis concentrated on important meteorological variables, such as temperature, precipitation, water vapor, wind components, and tropopause pressure, examining them in multiple seasons and pressure levels. MERRA-2 demonstrates comparable seasonal and spatial variations in temperature relative to AIRS observations, with strong correlations (r&lt;sup&gt;2&lt;/sup&gt; &amp;gt; 0.85) and root mean square errors (RMSE) ranging from 0.9 K to 2.5 K near the surface, decreasing to approximately 1 K at higher altitudes. However, MERRA-2 exhibits a cold bias closer to the surface and warm biases in the upper troposphere. Water vapor profiles reveal a wet bias, particularly in the lower to mid-troposphere, with RMSE increasing with altitude, from less than 20 % at 1000 hPa to more than 75 % at 300 hPa. Significant discrepancies are found in zonal wind estimates in the lower troposphere, especially over the Tibetan region, where MERRA-2 overestimates wind speeds. Below 700 hPa, Zonal winds show mean biases (MB) from &amp;minus;0.7 to 1.5 m s&lt;sup&gt;-1&lt;/sup&gt; and RMSEs between 0 m s&lt;sup&gt;-1&lt;/sup&gt; and 2.2 m s&lt;sup&gt;-1&lt;/sup&gt;. Agreement improves above 700 hPa, with MBs ranging from &amp;minus;0.5 to 0.6 m s&lt;sup&gt;-1&lt;/sup&gt;, and zonal wind estimates outperform meridional winds (RMSE: 0 m s&lt;sup&gt;-1 &lt;/sup&gt;- 4.4 m s&lt;sup&gt;-1&lt;/sup&gt;). MERRA-2 reasonably captures the spatial distribution and intensity of precipitation but overestimates rainfall over complex terrain during the summer monsoon by up to 20 mm d&lt;sup&gt;-1&lt;/sup&gt; compared to TRMM data. Tropopause pressure comparisons show good agreement with AIRS (MB: &amp;minus;2 to 3 hPa; RMSE: 2 hPa&amp;ndash;4 hPa), though larger biases are evident against radiosonde data (MB: 11 hPa&amp;ndash;29 hPa). These findings underscore the robustness of MERRA-2 in representing regional meteorological variability over the Indian region, while also highlighting specific biases, particularly in the lower troposphere and over complex terrain, that require careful consideration. As MERRA-2 data are frequently used as input for climate and chemical transport models, identifying and quantifying these biases is essential for improving model accuracy and enhancing the reliability of atmospheric simulations. This study offers critical insights for developing more robust modelling frameworks.</p>
</abstract>
<counts><page-count count="31"/></counts>
</article-meta>
</front>
<body/>
<back>
</back>
</article>