<div class="eI0">
  <div class="eI1">Modell:</div>
  <div class="eI2"><h2>MERRA (MODERN-ERA RETROSPECTIVE ANALYSIS FOR RESEARCH AND APPLICATIONS)</h2></div>
 </div>
 <div class="eI0">
  <div class="eI1">Aktualisierung:</div>
  <div class="eI2">hourly to monthly from 1980 to last month</div>
 </div>
 <div class="eI0">
  <div class="eI1">Greenwich Mean Time:</div>
  <div class="eI2">12:00 UTC = 13:00 MEZ</div>
 </div>
 <div class="eI0">
  <div class="eI1">Aufl&ouml;sung:</div>
  <div class="eI2">0.5&deg; x 0.65&deg;</div>
 </div>
 <div class="eI0">
  <div class="eI1">Parameter:</div>
  <div class="eI2">Cloud cover (low,middle,high,total)</div>
 </div>
 <div class="eI0">
  <div class="eI1">Beschreibung:</div>
  <div class="eI2">

Clouds are vertically divided into three levels: low, middle, and high. Each level is defined by the range of levels at which each type of clouds typically appears.<br><br>
<table  border="0" cellpadding="2" cellspacing="2" style="width:100%">
<tbody><tr>
<th>Level</th>
<th>Polar Region</th>
<th>Temperate Region</th>
<th>Tropical Region</th>
</tr>

<tr  align="center">
<th  align="left">High Clouds</th>
<td >10,000-25,000 ft<br>(3-8 km)</td>
<td>16,500-40,000 ft<br>(5-13 km)</td>
<td>20,000-60,000 ft<br>(6-18 km)</td>
</tr>

<tr align="center">
<th align="left">Middle Clouds</th>
<td>6,500-13,000 ft<br>(2-4 km)</td>
<td>6,500-23,000 ft<br>(2-7 km)</td>
<td>6,500-25,000 ft<br>(2-8 km)</td>
</tr>

<tr class="even" align="center">
<th  align="left">Low Clouds</th>
<td>Surface-6,500 ft<br>(0-2 km)</td>
<td>Surface-6,500 ft<br>(0-2 km)</td>
<td>Surface-6,500 ft<br>(0-2 km)</td>
</tr>
</tbody></table>
 <br><br>The types of clouds are:<br><br>
High clouds: Cirrus (Ci), Cirrocumulus  (Cc), and Cirrostratus (Cs). They are typically thin and white in appearance, but can appear in a magnificent array of colors when the sun is low on the horizon.<br><br>
Middle clouds: Altocumulus (Ac), Altostratus (As).  They are composed primarily of water droplets, however, they can also be composed of ice crystals when temperatures are low enough.<br><br>
 Low clouds: Cumulus (Cu), Stratocumulus (Sc), Stratus (St), and Cumulonimbus (Cb) are low clouds composed of water droplets.
<br>

    
  </div>
 </div>
 <div class="eI0">
  <div class="eI1">MERRA:</div>
  <div class="eI2">The MERRA time period covers the modern era of remotely sensed data, from 1979 through the present, and the special focus of the atmospheric assimilation is the hydrological cycle. Previous long-term reanalyses of the Earth's climate had high levels of uncertainty in precipitation and inter-annual variability. The GEOS-5 data assimilation system used for MERRA implements Incremental Analysis Updates (IAU) to slowly adjust the model states toward the observed state. The water cycle benefits as unrealistic spin down is minimized. In addition, the model physical parameterizations have been tested and evaluated in a data assimilation context, which also reduces the shock of adjusting the model system. Land surface processes are modeled with the state-of-the-art GEOS-5 Catchment hydrology land surface model. MERRA thus makes significant advances in the representation of the water cycle in reanalyses.</br>
</div></div>
<div class="eI0">
  <div class="eI1">Reanalyse:</div>
  <div class="eI2">Retrospective-analyses (or reanalyses) integrate a variety of observing systems with numerical models to produce a temporally and spatially consistent synthesis of observations and analyses of variables not easily observed. The breadth of variables, as well as observational influence, make reanalyses ideal for investigating climate variability. The Modern Era-Retrospective Analysis for Research and Applications supports NASA's Earth science objectives, by applying the state-of-the-art GEOS-5 data assimilation system that includes many modern observing systems (such as EOS) in a climate framework.<br></div></div>
</div>