The attributions of two extreme high temperature events in china were conducted based on single- and two-

step attribution methods, respectively.

  The spring of 2014 was the third warmest spring in Northern China since reliable observations were

established in the late 1950s. We used a two-step attribution method to investigate the relative contribution

from natural and human caused forcings to this event. The relation between mean temperature and high

temperature evens are first built in the region. Then the detection of mean temperature were conducted

based on the fingerprinting method. The results show that the anthropogenic forcing may have

contributed to an 11-fold increased in the chance of the 2014 spring extreme high temperature event in

Northern China.

  The 2015 summer was very hot in Western China with new records for the daily maximum temperature in

many stations in the region. The regional average of annual maxima of daily maximum (TXx) and daily

minimum temperatures (TNx) reached their historical highs. It is interesting to find that anthropogenic

influence can be directly detected in the extreme indices themselves at such a small regional scale.

So the human influence can be estimated directly on the output of the optimal detection results. The

preliminary results show that anthropogenic forcing may increase the occurrence of such events by at

least 3-fold for TXx and 42-fold for TNx.