PML_V2 global evapotranspiration and gross primary production (2000.02-2023.12)

<h2>Summary</h2> <p>This data is an <strong>8-day 5km (0.05&deg;)</strong> data aggregated from the latest <strong>8day 500m PML-V2 global evapotranspiration and gross primary production data</strong> in Google Earth Engine, available since 2000.2.26 to 2023 (latest and will update annually).</p> <p><strong>Notes</strong></p> <ul> <li> <p>8-day means an average of the variable for the 8 days (xx d-1).</p> </li> <li> <p>Land evapotranspiration (ET) can be computed as a sum of Ec, Ei, and Es, while in water, Penman evapotranspiration denotes actual evaporation (ET_water).</p> </li> <li> <p>In a 5km resolution, please do not add ET_water to land ET as they represent a different coverage of area within the 5km pixel. Please see the coverage ratio file for each variable.</p> </li> </ul> <table> <tbody> <tr> <th>BandName</th> <th>Units</th> <th>Scale</th> <th>Description</th> </tr> </tbody> <tbody> <tr> <td>GPP</td> <td>gC m-2 d-1</td> <td>0.01</td> <td>Gross primary product</td> </tr> <tr> <td>Ec</td> <td>mm d-1</td> <td>0.01</td> <td>Vegetation transpiration</td> </tr> <tr> <td>Es</td> <td>mm d-1</td> <td>0.01</td> <td>Soil evaporation</td> </tr> <tr> <td>Ei</td> <td>mm d-1</td> <td>0.01</td> <td>Interception from vegetation canopy</td> </tr> <tr> <td>ET_water</td> <td>mm d-1</td> <td>0.01</td> <td>Water body, snow and ice evaporation. Penman &lt;br&gt;evapotranspiration is regarded as actual evaporation for them.</td> </tr> </tbody> </table> <h2>Changes</h2> <p>Here, this PML-V2 dataset denotes <strong>the latest update</strong> that follows the original implementation of Zhang et al., 2019, <strong>except with </strong>Terra LAI for longer temporal coverage and annual updates.</p> <ul> <li> <p>Temporal coverage lengthened to 2000.2-2023.12</p> </li> <li> <p>Using MODIS Terra LAI (MOD15A2H) with original wWhd smoother processing as in Kong et al., 2019</p> </li> <li> <p>Recalibrated with the new MODIS Terra LAI</p> </li> <li> <p>Other climatic forcing and MODIS input remain the same</p> </li> </ul> <h2>Google Earth Engine</h2> <p>Original 500m 8-day data in GEE</p> <p>https://developers.google.com/earth-engine/datasets/catalog/CAS_IGSNRR_PML_V2_v018</p> <h2>Methods</h2> <p>Penman-Monteith-Leuning Evapotranspiration V2 (PML_V2) products include evapotranspiration (ET), its three components, and gross primary product (GPP) at 500m and 8-day resolution during 2000-2017 and with spatial range from -60&deg;S to 90&deg;N. The major advantages of the PML_V2 products are:</p> <ol> <li> <p>coupled estimates of transpiration and GPP via canopy conductance (Gan et al., 2018; Zhang et al., 2019)</p> </li> <li> <p>partitioning ET into three components: transpiration from vegetation, direct evaporation from the soil and vaporization of intercepted rainfall from vegetation (Zhang et al., 2016).</p> </li> </ol> <p>The PML_V2 products perform well against observations at 95 flux sites across globe, and are similar to or noticeably better than major state-of-the-art ET and GPP products widely used by water and ecology science communities (Zhang et al., 2019).</p> <h2>References</h2> <ul> <li> <p>Zhang, Y., Kong, D., Gan, R., Chiew, F.H.S., McVicar, T.R., Zhang, Q., and Yang, Y., 2019. Coupled estimation of 500m and 8-day resolution global evapotranspiration and gross primary production in 2002-2017. Remote Sens. Environ. 222, 165-182, <a href="https://doi.org/10.1016/j.rse.2018.12.031">doi:10.1016/j.rse.2018.12.031</a></p> </li> <li> <p>Gan, R., Zhang, Y.Q., Shi, H., Yang, Y.T., Eamus, D., Cheng, L., Chiew, F.H.S., Yu, Q., 2018. Use of satellite leaf area index estimating evapotranspiration and gross assimilation for Australian ecosystems. Ecohydrology, <a href="https://doi.org/10.1002/eco.1974">doi:10.1002/eco.1974</a></p> </li> <li> <p>Zhang, Y., Pe&ntilde;a-Arancibia, J.L., McVicar, T.R., Chiew, F.H.S., Vaze, J., Liu, C., Lu, X., Zheng, H., Wang, Y., Liu, Y.Y., Miralles, D.G., Pan, M., 2016. Multi-decadal trends in global terrestrial evapotranspiration and its components. Sci. Rep. 6, 19124. <a href="https://doi.org/10.1038/srep19124">doi:10.1038/srep19124</a></p> </li> </ul>