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<figure><img src="image_38.png" /></figure>

G-VAP Archive V2 Ensemble for the common period January 2005 to December 2009

<figure><img src="image_39.png" /><figcaption>**Figure 5.** Seasonal maps of the mean archive ensemble total column water vapour (TCWV) over the common period 2005-2009. Also included is the standard deviation of the seasonal mean ($\sigma$), the respective coefficient of variance (CV), and the difference between the seasonal maximum and minimum TCWV values ($TCWV_{max}$-$TCWV_{min}$). While the largest (absolute) variability is seen in the Tropics, the greater relative difference (>50%) is found in polar regions.</figcaption></figure>
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<figure><img src="image_40.png" /></figure>

<figure><img src="image_41.png" /></figure>

<figure><img src="image_42.png" /><figcaption>**Figure 6.** Global TCWV differences of each archive member to the ensemble mean for the common period 2005-2009. Average global differences have been summed and then normalised by the ensemble mean TCWV. For records that have missing data over land or polar regions, the ensemble mean is recalculated to account for differences, excluding these areas with missing data.</figcaption></figure>
<figure><img src="image_43.png" /></figure>

TCWV Bias Relative to Ensemble Mean (2005-2009)

<figure><img src="image_44.png" /><figcaption>**Figure 7.** Ensemble member total column water vapour (TCWV) biases relative to the ensemble mean for the common period of all records (see Figure 1).</figcaption></figure>
<figure><img src="image_45.png" /></figure>

<figure><img src="image_46.png" /><figcaption>**Figure 8.** Trend estimates in total column water vapour (TCWV) in kg/m² per decade for data records that span the common 'long' period (1988-2014) for global land (a) and ice-free oceans (b) between ±60°. Trends are represented as black dots with the estimated uncertainty of the trend shown in vertical bars. Also shown on the right-hand y-axes are the regression coefficient (%/K) for each data record. Regression has been carried out against sea surface temperature (SST) from the ESA Climate Change Initiative (CCI) and 2-metre air temperature (T2m) from ERA5. These are shown as blue squares and green triangles, respectively, with the regression error as vertical bars. The grey-shaded region on the bottom figure denotes the expected range of regression values and actual expectation based on the mean change in SST (Wentz and Schabel, 2000).</figcaption></figure>
<figure><img src="image_47.png" /></figure>

<figure><img src="image_48.png" /></figure>

<figure><img src="image_49.png" /></figure>

<figure><img src="image_50.png" /><figcaption>**Figure 9.** Mean absolute deviation (MAD) of archive total column water vapour (TCWV) trend estimates for the period between 1988-2014 (a). High MAD values observed in the Tropics are on the order 25% of observed trends, while the highest MAD values (>1.2 kg/m²/decade) are observed at high latitudes and are related to sea ice. Application of the sea-ice mask (see Figure ??) to the microwave (MW) records removes these effects seen at high latitudes (b), while the high variability seen in the tropics is related to the Infrared (IR) only products (c).</figcaption></figure>
<figure><img src="image_51.png" /></figure>

<figure><img src="image_52.png" /></figure>

<figure><img src="image_53.png" /><figcaption>**Figure 10.** Anomaly time series of TCWV, averaged over the global ice-free ocean within 60°N/S, from members of the G-VAP data archive that cover the period 1988-2014. Each average of the TCWV time series was added to each anomaly time series in order to visualise biases between the data records. Vertical lines denote observed breakpoints using the same colour bar as for the anomaly time series. The vertical line is plotted in bold in case the PMF and SNH tests both detected the breakpoint.</figcaption></figure>
<figure><img src="image_54.png" /></figure>

<figure><img src="image_55.png" /></figure>

<figure><img src="image_56.png" /><figcaption>Figure 11. As Figure 10 but for global land regions within 60°N/S.</figcaption></figure>
<figure><img src="image_57.png" /></figure>

<figure><img src="image_58.png" /><figcaption>**Figure 12.** Global maps of the correlation between ERA5 total column water vapour (TCWV) and the North Atlantic Oscillation (NAO), El Niño Southern Oscillation Index 3.4 (NINO3.4), Pacific Decadal Oscillation (PDO) climate indices. The stippling indicates areas where the correlation is within the 95% confidence level.</figcaption></figure>
<figure><img src="image_59.png" /></figure>

<figure><img src="image_60.png" /><figcaption>**Figure 13.** Summary of global regions where the water vapour records that cover the long period (1988-2014) significantly correlate with the different climate indices. Negative correlations are shown in orange on the left, and positive correlations are shown in purple on the right. Areas coloured in the lighter shade of colour indicate where at least 50% of all water vapour datasets show significant correlations, while darker-coloured areas indicate where 100% of records show significant correlations to the climate indices.</figcaption></figure>
<figure><img src="image_61.png" /></figure>

<figure><img src="image_62.png" /></figure>

G-VAP Archive V2 Long Period (1988-01 to 2014-12)

<figure><img src="image_63.png" /></figure>

**Figure A1.** Global maps of total column water vapour (TCWV) trend estimates from all records between 1988 and 2014. Regions where trends were not statistically significant are highlighted with stippling. These regions tend to coincide with stronger trends; however, it should be noted that the reported trends by G-VAP are used to identify issues rather than an analysis of climate change. Therefore, it is more likely these areas experience higher ranges of variability, which introduces noise into the calculation (Weatherhead et al., 1998) Thus, longer time series are required to improve confidence in reported trends.
<figure><img src="image_64.png" /></figure>

<figure><img src="image_65.png" /><figcaption>**Table 1.** Details of data records from version 1 of the G-VAP archive and their status within the version 2 release. Version 1 of the archive is available from https://doi.org/10.5676/EUM_SAF_CM/G-VAP/V001.</figcaption></figure>

<table><thead><tr><th></th><th>Data record</th><th>status</th></tr></thead><tbody><tr><td>1</td><td>AIRWAVE</td><td>superseded by version 2 (Castelli et al., 2019)*</td></tr><tr><td>2</td><td>ATOVS CM SAF</td><td>extended coverage</td></tr><tr><td>3</td><td>AMSR-E JAXA</td><td>extended coverage and inclusion of AMSR2</td></tr><tr><td>4</td><td>AMSR-E REMSS</td><td>not used</td></tr><tr><td>5</td><td>EMiR</td><td>extended coverage</td></tr><tr><td>6</td><td>ERA-Interim</td><td>extended coverage</td></tr><tr><td>7</td><td>ERA-20C</td><td>extended coverage</td></tr><tr><td>8</td><td>GOME/SCIAMACHY/GOME-2 GlobVapour</td><td>superseded by new product</td></tr><tr><td>9</td><td>HIRS UWisconsin</td><td>extended coverage</td></tr><tr><td>10</td><td>HOAPS SSM/I V3</td><td>superseded by version 4</td></tr><tr><td>11</td><td>JRA-55</td><td>extended coverage</td></tr><tr><td>12</td><td>Merged Microwave REMSS</td><td>extended coverage</td></tr><tr><td>13</td><td>MERIS GlobVapour</td><td>not used</td></tr><tr><td>14</td><td>MERRA</td><td>extended coverage</td></tr><tr><td>15</td><td>MERRA-2</td><td>extended coverage</td></tr><tr><td>16</td><td>MODIS NIR & IR Aqua NASA (MYD08_M3**)</td><td>extended coverage and inclusion of MODIS Terra (MOD08_M3) and IR products from both Aqua & Terra</td></tr><tr><td>17</td><td>NCEP CFSR</td><td>extended using CFSv2</td></tr><tr><td>18</td><td>nnHIRS</td><td>extended coverage</td></tr><tr><td>19</td><td>NVAP-M Climate</td><td>extended coverage</td></tr><tr><td>20</td><td>NVAP-M Ocean</td><td>not used</td></tr><tr><td>21</td><td>SSM/I+MERIS GlobVapour</td><td>superseded by new product</td></tr><tr><td>22</td><td>TMI REMSS</td><td>dropped</td></tr></tbody></table>

<footnote>* The AIRWAVEv2 data are available on request from the following authors: Elisa Castelli (e.castelli@isac.cnr.it), Enzo Papandrea (e.papandrea@isac.cnr.it). ** Only NIR TCWV water vapour used in version 1 of the archive</footnote>
<figure><img src="image_66.png" /><figcaption>**Table 2.** Break points detected by the PMF and SNH tests and coincident events. Results are shown for the global ocean. The breakpoints are characterised by the time of the event (yyyy-mm) and their strength in kg m⁻². The strength of the breakpoint is printed in bold if both tests agree on the date within ±3 months. Break events marked with a "*" are taken from Schröder et al. (2019). Information on satellite status is taken from https://www.ospo.noaa.gov/Operations/POES/status.html.</figcaption></figure>

<table><thead><tr><th>Data record</th><th>Date PMF</th><th>Breaksize PMF</th><th>SNH</th><th>Event</th></tr></thead><tbody><tr><td colspan="5">global ocean</td></tr><tr><td rowspan="3">ERA-Interim</td><td>1991-12</td><td><strong>-0.48</strong></td><td><strong>-0.50</strong></td><td>Approximate i) end of assimilation of F08 data, ii) start of assimilation of F10 data, and iii) end of assimilation of NOAA10 [1]*</td></tr><tr><td>1995-12</td><td><strong>-0.24</strong></td><td><strong>-0.14</strong></td><td>Approximate start of assimilation of F13 data [1]</td></tr><tr><td>2006-06</td><td>0.18</td><td></td><td>Approximate i) end of assimilation of F15 and NOAA14 data, ii) change from GOES10 to GOES11, and iii) start of assimilation of Meteosat 5 and 8 data, see [1], see text*</td></tr><tr><td rowspan="14">ERA5</td><td>1991-02</td><td>-0.22</td><td></td><td>Approximate start of assimilation of F10 data</td></tr><tr><td>1992-01</td><td><strong>-0.22</strong></td><td><strong>-0.35</strong></td><td>Approximate start of assimilation of F11 data [2]</td></tr><tr><td>1993-12</td><td>0.10</td><td></td><td>Approximate end of assimilation of F11 data [2]</td></tr><tr><td>1994-12</td><td>-0.27</td><td></td><td>Approximate i) end of assimilation of NOAA11 data, and ii) start of assimilation of F11 (after a 1 year interruption) [2]</td></tr><tr><td>1997-05</td><td>-0.11</td><td></td><td>Approximate i) start of assimilation of NOAA11 data, after a 2.5 year interruption, and ii) start/end of assimilation of F14/F10 [2]</td></tr><tr><td>2000-11</td><td>0.12</td><td></td><td>Approximate start of assimilation of NOAA16 data [2]</td></tr><tr><td>2002-06</td><td>0.12</td><td></td><td>Approximate start of assimilation of NOAA17 data [2]</td></tr><tr><td>2007-03</td><td>0.09</td><td></td><td>Approximate start of assimilation of Metop-A and Meteosat9 data [2]</td></tr><tr><td>2008-07</td><td>-0.13</td><td></td><td>Unclear</td></tr><tr><td>2009-07</td><td>-0.16</td><td></td><td>Approximate start of assimilation of NOAA19 and F17 data [2]</td></tr><tr><td>2013-06</td><td>-0.09</td><td></td><td>Approximate i) start of assimilation of FY-3B data, and ii) end of assimilation of NOAA19 data</td></tr><tr><td>HIRS UWisconsin</td><td>2001-03</td><td><strong>6.14</strong></td><td><strong>8.87</strong></td><td>NOAA16 operational since 2001-03 [2].</td></tr><tr><td>JRA55</td><td>2006-12</td><td><strong>0.22</strong></td><td><strong>0.16</strong></td><td>Launch of Metop-A in October 2006. Approximate end of assimilation of monthly surface meteorological data in China [3], see text</td></tr><tr><td rowspan="2">MERRA</td><td>1998-11</td><td><strong>0.54</strong></td><td><strong>0.53</strong></td><td>Start of assimilation of NOAA15 in July 1998. Note: assimilation of AMSU-A & AMSU-B (NOAA15) started on 1998-11-01, while assimilation of HIRS data (NOAA15) began on 1998-07-02 [4]*</td></tr><tr><td>2009-09</td><td>-0.47</td><td></td><td>Approximate end of assimilation of F13 data</td></tr></tbody></table>

references: [1] Dee et al. (2011); [2] Hersbach et al. (2020); [3] Kobayashi et al. (2015); [4] Rienecker et al. (2011); [5] McCarty et al. (2016); [6] Gelaro et al. (2017); [7] Saha et al. (2010); [8] Schröder et al. (2016); [9] Slivinski et al. (2019)
<figure><img src="image_67.png" /><figcaption>**Table 2.** Table 2 continued</figcaption></figure>

<table><thead><tr><th>Data record</th><th>Date PMF</th><th>Breaksize PMF</th><th>SNH</th><th>Event</th></tr></thead><tbody><tr><td colspan="5"><strong>global ocean</strong></td></tr><tr><td rowspan="4">MERRA2</td><td>1991-02</td><td><strong>-0.31</strong></td><td><strong>-0.33</strong></td><td>Start of assimilation of F10 data on 1990-12-09 [5]*</td></tr><tr><td>1994-11</td><td><strong>-0.11</strong></td><td><strong>-0.15</strong></td><td>Approximate end of assimilation of NOAA11 data [5]</td></tr><tr><td>2003-07</td><td><strong>0.13</strong></td><td><strong>0.09</strong></td><td>No obvious coincidence with a change in space-based water vapour sensors; approximate end of assimilation of data from AMSU-A on NOAA17; strong drop in assimilated wind observations from ERS2 in June 2003 [5]</td></tr><tr><td>2007-09</td><td><strong>0.13</strong></td><td><strong>0.10</strong></td><td>Approximate start of assimilation of surface wind from WindSat in 2007-08, strong increase in the number of assimilated AMVs from JMA and a decrease in the number of assimilated AMVs from MODIS [5,6]*</td></tr><tr><td>2009-08</td><td><strong>-0.21</strong></td><td><strong>-0.22</strong></td><td>Approximate start and end of assimilation from various satellite data in April, November &amp; December 2009; end of assimilation of rain rates from SSM/I in September 2009 [5]</td></tr><tr><td rowspan="3">NCEP CFSR/CFSv2</td><td>1998-10</td><td><strong>1.07</strong></td><td><strong>1.20</strong></td><td>Approximate start of i) assimilation of NOAA15 data, and end of assimilation of NOAA11 &amp; NOAA14; change from assimilating GOES09 to GOES10 [7]*</td></tr><tr><td>2001-01</td><td><strong>0.46</strong></td><td><strong>0.33</strong></td><td>Approximate start of assimilation of data from NOAA16 [7]</td></tr><tr><td>2011-04</td><td>-0.32</td><td></td><td>Unclear</td></tr><tr><td rowspan="4">NCEP-DOE 2</td><td>1991-06</td><td><strong>-0.26</strong></td><td><strong>-0.32</strong></td><td>Unclear</td></tr><tr><td>2005-06</td><td>0.29</td><td></td><td>Unclear</td></tr><tr><td>2006-12</td><td><strong>0.24</strong></td><td><strong>0.21</strong></td><td>Unclear</td></tr><tr><td>2008-02</td><td><strong>-0.34</strong></td><td><strong>-0.42</strong></td><td>Unclear</td></tr><tr><td rowspan="2">NNHIRS</td><td>1993-02</td><td><strong>-0.88</strong></td><td><strong>-0.52</strong></td><td>See [8] for discussion on the results related to NVAP-M. It seems that nnHIRS also exhibits increased uncertainties then.*</td></tr><tr><td>2002-10</td><td>0.52</td><td></td><td>NOAA-17 is operational since 2002-10</td></tr><tr><td rowspan="2">NOAA 20CR V2C</td><td>2008-10</td><td>-0.28</td><td></td><td>Unclear</td></tr><tr><td>2012-11</td><td><strong>-0.48</strong></td><td><strong>-0.39</strong></td><td>Approximate change in the source of in-situ SST data [9]</td></tr><tr><td rowspan="2">NOAA 20CR V3</td><td>1991-06</td><td><strong>-0.24</strong></td><td><strong>-0.25</strong></td><td>Unclear</td></tr><tr><td>2008-07</td><td>-0.31</td><td></td><td>Unclear</td></tr><tr><td rowspan="2">REMSS V7</td><td>1993-06</td><td><strong>0.24</strong></td><td><strong>0.11</strong></td><td>See [8]*</td></tr><tr><td>2001-07</td><td><strong>0.14</strong></td><td><strong>0.06</strong></td><td>see text</td></tr></tbody></table>

references: [1] Dee et al. (2011); [2] Hersbach et al. (2020); [3] Kobayashi et al. (2015); [4] Rienecker et al. (2011); [5] McCarty et al. (2016); [6] Gelaro et al. (2017); [7] Saha et al. (2010); [8] Schröder et al. (2016); [9] Slivinski et al. (2019)
<figure><img src="image_68.png" /></figure>

<figure><img src="image_69.png" /><figcaption>**Table 3.** As Table 2 but for global land surfaces. For the following data records, no breakpoints were detected over land: JRA55, MERRA, and MERRA2.</figcaption></figure>

<table><thead><tr><th>Data record</th><th>Date PMF</th><th>Breaksize PMF</th><th>SNH</th><th>Event</th></tr></thead><tbody><tr><td colspan="5">global land</td></tr><tr><td>ERA-Interim</td><td>2009-10</td><td><strong>-0.23</strong></td><td><strong>-0.18</strong></td><td>Approximate start of assimilation of AMSR-E and F16 data, see [1]</td></tr><tr><td rowspan="4">HIRS UWisconsin</td><td>1990-08</td><td><strong>3.86</strong></td><td><strong>3.42</strong></td><td>HIRS/2 on NOAA-10 became very noisy. Early HIRS/2 data is an outlier because of the missing split window (12 µm) band.</td></tr><tr><td>1991-08</td><td><strong>-1.74</strong></td><td><strong>-2.03</strong></td><td>NOAA12 is operational since 1991-09.</td></tr><tr><td>1998-11</td><td><strong>1.63</strong></td><td><strong>1.65</strong></td><td>NOAA15 is operational since 1998-12.</td></tr><tr><td>2001-03</td><td><strong>3.48</strong></td><td><strong>4.82</strong></td><td>NOAA16 operational since 2001-03.</td></tr><tr><td rowspan="2">NCEP CFSR/CFSv2</td><td>2004-03</td><td><strong>0.52</strong></td><td><strong>0.41</strong></td><td>Approximate start of assimilation of data from AIRS and AMSU-A onboard MODIS-Aqua [7].</td></tr><tr><td>2007-06</td><td><strong>0.47</strong></td><td><strong>0.40</strong></td><td>Approximate start of assimilation of data from Metop-A [7].</td></tr><tr><td rowspan="3">NCEP-DOE 2</td><td>1991-01</td><td><strong>-0.2</strong></td><td><strong>-0.14</strong></td><td>Unclear</td></tr><tr><td>1996-05</td><td>0.16</td><td></td><td>Approximate date of new snow climatology.</td></tr><tr><td>2007-03</td><td><strong>0.30</strong></td><td><strong>0.25</strong></td><td>Unclear</td></tr><tr><td>NNHIRS</td><td>1995-08</td><td>-1.15</td><td></td><td>The break does not seem to coincide with a change in NOAA satellites. It marks the end of a period of approximately two years with a series of anomalies.</td></tr><tr><td>NOAA 20CR V2C</td><td>2012-09</td><td>-0.60</td><td></td><td>Unclear</td></tr><tr><td>NOAA 20CR V3</td><td>2007-12</td><td>-0.43</td><td></td><td>Unclear</td></tr></tbody></table>

references: [1] Dee et al. (2011); [2] Hersbach et al. (2020); [3] Kobayashi et al. (2015); [4] Rienecker et al. (2011); [5] McCarty et al. (2016); [6] Gelaro et al. (2017); [7] Saha et al. (2010); [8] Schröder et al. (2016); [9] Slivinski et al. (2019)
<figure><img src="image_70.png" /><figcaption>**Table A1.** Overview of utilised abbreviations and their definitions</figcaption></figure>

<table><thead><tr><td>Abbreviation</td><td>Definition</td></tr></thead><tbody><tr><td>AIRS</td><td>Atmospheric Infrared Sounder</td></tr><tr><td>AIRWAVE</td><td>Advanced InfraRed Water Vapour Estimator</td></tr><tr><td>AMSR2</td><td>Advanced Microwave Scanning Radiometer 2</td></tr><tr><td>AMSR-E</td><td>Advanced Microwave Scanning Radiometer for EOS</td></tr><tr><td>AMIP</td><td>Atmospheric Model Intercomparison Project</td></tr><tr><td>AR6</td><td>Sixth Assessment Report</td></tr><tr><td>ATOVS</td><td>Advanced TIROS Operational Vertical Sounder</td></tr><tr><td>CFSR</td><td>Climate Forecast System Reanalysis</td></tr><tr><td>CFSv2</td><td>Coupled Forecast System model Version 2</td></tr><tr><td>CM SAF</td><td>Satellite Application Facility on Climate Monitoring</td></tr><tr><td>ECMWF</td><td>European Centre for Medium-Range Weather Forecasts</td></tr><tr><td>ENSO</td><td>El Niño Southern Oscillation</td></tr><tr><td>EMiR</td><td>ERS/Envisat MWR Recalibration and Water Vapour TDR Generation</td></tr><tr><td>ERA-Interim</td><td>ECMWF Interim Reanalysis</td></tr><tr><td>ERA-20C</td><td>ECMWF 20<sup>th</sup> Century Reanalysis</td></tr><tr><td>ERA5</td><td>ECMWF Reanalysis v5</td></tr><tr><td>ESA</td><td>European Space Agency</td></tr><tr><td>EUMETSAT</td><td>European Organisation for the Exploitation of Meteorological Satellites</td></tr><tr><td>GDAP</td><td>Data and Assessments Panel</td></tr><tr><td>GEWEX</td><td>Global Energy and Water cycle Exchanges</td></tr><tr><td>GOME/GOME-2</td><td>Global Ozone Monitoring Experiment</td></tr><tr><td>GOME EVOL</td><td>GOME Evolution</td></tr><tr><td>G-VAP</td><td>GEWEX Water Vapor Assessment</td></tr><tr><td>HIRS</td><td>High-Resolution Infrared Sounder</td></tr><tr><td>HOAPS</td><td>Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data</td></tr><tr><td>JAXA</td><td>Japan Aerospace Exploration Agency</td></tr><tr><td>JMA</td><td>Japan Meteorological Agency</td></tr><tr><td>JRA-55</td><td>Japanese 55-year Reanalysis</td></tr><tr><td>MAD</td><td>Median absolute deviation</td></tr><tr><td>MERIS</td><td>Medium Resolution Imaging Spectrometer</td></tr><tr><td>MERRA</td><td>Modern-Era Retrospective analysis for Research and Applications</td></tr></tbody></table>
<figure><img src="image_71.png" /></figure>

<figure><img src="image_72.png" /><figcaption>**Table A1.** Table A1 continued.</figcaption></figure>

<table><thead><tr><td>Abbreviation</td><td>Definition</td></tr></thead><tbody><tr><td>MERRA-2</td><td>MERRA Version 2</td></tr><tr><td>MODIS</td><td>Moderate-resolution Imaging Spectroradiometer</td></tr><tr><td>MPIC</td><td>Max Planck Institute for Chemistry</td></tr><tr><td>NASA</td><td>National Aeronautics and Space Administration</td></tr><tr><td>NCEP</td><td>National Centers for Environmental Prediction</td></tr><tr><td>NIR</td><td>Near-infrared</td></tr><tr><td>nnHIRS</td><td></td></tr><tr><td>NOAA</td><td>National Oceanic and Atmospheric Administration</td></tr><tr><td>NVAP</td><td>NASA Water Vapor Project</td></tr><tr><td>NVAP-M</td><td>NVAP - Making Earth Science Data Records for Research Environments</td></tr><tr><td>MW</td><td>Microwave</td></tr><tr><td>OLCI</td><td>Ocean and Land Colour Instrument</td></tr><tr><td>OMI</td><td>Ozone Monitoring Instrument</td></tr><tr><td>PROES</td><td>process evaluation studies</td></tr><tr><td>REMSS</td><td>Remote Sensing Systems</td></tr><tr><td>SCIAMACHY</td><td>SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY</td></tr><tr><td>SSM/I</td><td>Special Sensor Microwave Imager</td></tr><tr><td>SSMIS</td><td>Special Sensor Microwave Imager/Sounder</td></tr><tr><td>TCWV</td><td>Total Column Water Vapour</td></tr><tr><td>TIROS</td><td>Television Infrared Observation Satellite</td></tr><tr><td>TMI</td><td>Tropical Rainfall Measuring Mission's Microwave Imager</td></tr><tr><td>WCRP</td><td>World Climate Research Panel</td></tr><tr><td>WVCCI</td><td>Water Vapour Climate Change Initiative</td></tr></tbody></table>
<figure><img src="image_73.png" /><figcaption>**Table B1.** Climate indices used in this study.</figcaption></figure>

<table><thead><tr><td>Index</td><td>Description</td><td>Reference</td><td>Source</td></tr></thead><tbody><tr><td>AMM</td><td>Atlantic Meridional Mode. The AMM spatial pattern is defined via applying Maximum Covariance Analysis (MCA) to the sea surface temperature (SST) and the 10 m wind field over the time period 1950-2005 over the region 21°S to 32°N and 74°W to 15°E.</td><td>Chiang and Vimont (2004)</td><td>http://www.esrl.noaa.gov/psd/data/timeseries/monthly/AMM/</td></tr><tr><td>AO</td><td>Arctic Oscillation. The daily AO index is constructed by projecting the daily (00Z) 1000 hPa height anomalies pole ward of 20°N onto the loading pattern of the AO.</td><td>Thompson and Wallace (1998)</td><td>http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml</td></tr><tr><td>NAO</td><td>North Atlantic Oscillation. The principal component (PC)-based indices of the NAO are the time series of the leading EOF of sea level pressure anomalies over the Atlantic sector, 20°-80°N, 90°W-40°E.</td><td>Walker (1924), Rogers (1984), Barnston and Livezey (1987), &amp; Hurrell (1995)</td><td>http://www.esrl.noaa.gov/psd/data/climateindices/list/</td></tr><tr><td>NINO34</td><td>El Nino Southern Oscillation Index 3.4. Average SST anomaly in the region between 5°N and 5°S as well as 170°W and 120°W.</td><td>Walker (1924) &amp; Rasmusson and Carpenter (1982)</td><td>http://www.esrl.noaa.gov/psd/data/climateindices/list/</td></tr><tr><td>PDO</td><td>Pacific Decadal Oscillation. The PDO is defined as the leading principal component of North Pacific monthly sea surface temperature variability (poleward of 20N for the 1900-93 period).</td><td>Mantua et al. (1997) &amp; Zhang et al. (1997)</td><td>http://jisao.washington.edu/pdo/</td></tr><tr><td>PMM</td><td>Pacific Meridional Mode. Like AMM, the PMM pattern is defined via applying MCA to SST and the zonal and meridional components of the 10 m wind field for period 1950-2005 over the region (21°S-32°N, 74°W-15°E</td><td>Chiang and Vimont (2004)</td><td>https://psl.noaa.gov/data/timeseries/monthly/PMM/</td></tr></tbody></table>