Temporal variation of wind speed in China for 1961–2007

Abstract

Monthly observed wind speed data at 597 weather stations and NCEP wind speed data at 10 m above surface were used to explore the temporal variations of the wind speed for 1961-2007 in China. The results indicate that the temporal variation of annual wind speed in China has experienced four phases: two relatively steady periods from 1961 to 1968 and 1969 to 1974 with a sharp step change in 1969, a statistically significant decline stage from 1974 to 1990s, and another relatively steady period from 1990s to 2007. Except for the sharp step in 1969 being caused by the changes of observation instrument, other breakpoints correspond well with the positive and negative phases of the interdecadal Pacific oscillation. In addition, four different temporal variation patterns of annual wind speed in China have been identified by using cluster analysis and their spatial distributions were also explored.

Homogenization of Tianjin monthly near-surface wind speed using RHtestsV4 for 1951–2014

“…8, the wind speed series after adjustment at all 10 stations were coincident, with a reducing trend at the 95% significant level. This result is consistent with current researches on assessment of observed near-surface wind speed trends in China (Rong and Liang 2008;Cheng 2010;Zou et al 2010;Fu et al 2011;Guo et al 2011;Chen et al 2013;Zhang et al 2014;Xiong 2015), and also similar to trends reported for other parts of the world (Pryor et al 2009;Wan et al 2010;William and Martha 2014). Based on the adjusted data, the trends in the regional average annual and seasonal (spring, summer, autumn, and winter) wind speed series were −0.277, −0.325, −0.228, −0.223, and −0.336 m s −1 /10a, respectively (Fig.…”

“…Therefore, it is necessary to homogenize climate data before assessing interannual and multidecadal variabilities in wind speed (Pryor et al 2009;Fu et al 2011;Chen et al 2013;William and Martha 2014). Wind speed is a random variable easily influenced by the underlying surface, especially for monthly or daily observations, and time series tend to fluctuate due to local climate effects.…”

Wind speed trends over China: quantifying the magnitude and assessing causality

“…The proportion of stations exhibiting an upward trend over China is larger than that estimated by Fu et al (2011) and Guo et al (2010), but still represents only a small fraction of the total number of time series considered. Fifty-four percent of grid cells in the NCEP/NCAR product exhibit significant negative trends, while 3% show increases.…”

“…Because there is a strong seasonality in wind speed variations in China (Fu et al, 2011;Guo et al, 2010) and seasonality is an important element to measure climate, and further can be used as a diagnostic of the validity of the reanalysis data products. Here we use the seasonality index (SI) proposed by Walsh and Lawler (1981) to quantify the wind speeds seasonality in China:…”

“…The lack of correspondence between observational and reanalysis data sets and between observational data sets may derive from differences in time-series duration (and the short time-series of wind speed that are available for analysis), changes in station location, measurement height, data recording procedures and instrumentation deployed, in addition to difficulties in developing homogeneous observed records of near-surface wind speed (Pryor et al, 2009;Fu et al, 2011;Wan et al, 2010). Further, mid-latitude wind speeds exhibited high variability at interannual to interdecadal time scales linked to seasonal variation of the atmospheric circulation and internal modes of climate variability (Enloe et al, 2004;Pryor et al, 2005, Park et al, 2010Pryor and Ledolter, 2010) which further confounds identification of robust trends and attribution thereof.…”