Simmonds I. Bi DH. Hope P. <br>
<b>
Atmospheric water vapor flux and its association with rainfall over China in<br>
  summer<br>
<DD>  Journal of Climate. 12(5 Part 2):1353-1367, 1999 May.<br>
</B>
<P>
</DD><DT><STRONG>Abstract</STRONG></DT>
<DD>  The summer moisture transport by the large-scale circulation over China has
  been investigated using ECMWF-WMO twice-daily analyses for the period
  1980-96. The horizontal flux of atmospheric water vapor and its divergence
  has been calculated over two target regions, namely, southeast China (25
  degrees-35 degrees N, 110 degrees-120 degrees E) and northeast China (40
  degrees-50 degrees N, 120 degrees-130 degrees E). The time-averaged fluxes
  show the southeastern Asian and Indian monsoon circulations bringing abundant
  moisture from the South China Sea and the Bay of Bengal, respectively, to
  southeast China while the midlatitude westerlies dominate the moisture
  transport over northeast China.
The association between the interannual variations of moisture flux and
  rainfall over China has been examined. The comparison of the fluxes for wet
  and dry years over the southeast showed there to be, for the former, much
  stronger moisture transport by the southeastern Asian monsoon through the:
  southern boundary but little change associated with transport by the Indian
  monsoon. Furthermore, comparison between mean and transient eddy transport
  budgets in wet and dry years and in the climatological mean shows that the
  mean component is dominant in the total transport. The moisture convergence
  associated with the: transient eddies assumes its largest values in the
  eastern part of the country and, for the most part, assumes a sign opposite
  to that of the moisture flux convergence associated with the time-mean
  circulation and moisture fields, The results of this study suggest that the
  transient eddies do not play a significant role in the initiation and
  maintenance of the abnormal climate events over the two domains used in the
  study. Over both of these domains the two largest terms in the climatological
  moisture budget are seen to be the evaporation and the precipitation, while
  for interannual variations the largest terms are the atmospheric moisture
  convergence and thr precipitation;
China has the largest irrigated area in the world and much of this is in the
  form of flooded paddy fields. It is suggested that this large area of
  saturated surface may result in evapotranspiration rates that differ
  significantly from those implied by atlases that have used estimates obtained
  at 'typical" locations. The extent of irrigation over China may also make the
  task of interpreting its moisture budget more difficult. [References: 46]