太阳准周期变化对北半球夏季平流层加热率的影响

采用1979—2013年6—8月欧洲中期数值预报中心ERA-Interim逐月再分析资料和2004—2010年6—8月美国国家大气和海洋管理局太阳光谱辐照度资料,利用北京气候中心大气辐射模式,计算了北半球平流层夏季臭氧加热率(Ozone Heating Rate,OHR)和净加热率(Net Heating Rate,NHR),分析了太阳准11 a变化中太阳活动强年与弱年纬向平均OHR(NHR)的差异,并讨论了差异形成的原因。结果表明:太阳活动强年比弱年的紫外辐射明显要强,导致OHR、NHR整层增强,且随高度增加而增加;臭氧浓度在平流层下层较小,在平流层上层较大,该变化导致OHR、NHR有类似的变化型,且稍向高处偏移;OHR、NHR在平流层上层的变化,由紫外辐射和臭氧共同作用,其他地区均为臭氧起主要作用。

Influence of solar quasi-periodic variation on stratospheric heating rate in the Northern Hemisphere in summer

Ozone absorption of ultraviolet radiation is a main heat source and plays an important role in radiation balance of stratosphere.Solar cycle,especially ultraviolet radiation,can directly affect the stratospheric heating rate.According to the data from SIM(Spectral Irradiance Monitor) on the satellite SORCE,it indicates that the reduction of ultraviolet radiation is more than four to six times as prior research results in the weak solar activity years from 2004 to 2007.The variation of ultraviolet radiation can affect the stratospheric heating rate by changing ozone distribution.Through qualitative research,ozone concentration mixing ratio shows strong positive anomaly in lower stratosphere,and also indicates positive correlation with solar heating rate in upper stratosphere in the strong solar activity years.In addition,lots of studies of stratospheric radiation balance used the annual average data.However,BD(Brewer-Dobson) circulation relates with planetary wave effects and atmospheric thermal radiation plays a main role in stratospheric radiation balance in winter.To understand the essence,analysis of summer stratosphere is particularly significant.Thus,the main purpose of this paper is using the data of SIM and the mode of atmospheric radiation model to quantitatively study the effects of variations of ultraviolet radiation and ozone concentration mixing ratio in the solar cycle on the ozone heating rate(OHR) and the net heating rate(NHR).Based on the BCC-RAD Model,OHR and NHR in stratosphere in the Northern Hemisphere in summer are calculated by using the ERA-Interim monthly reanalysis data from European Centre for Medium-Range Weather Forecasts(ECMWF) during 1979-2013 and the solar spectral irradiance data from National Oceanic and Atmosphere Administration(NOAA) from 2004 to 2010.Variations of zonal mean OHR(NHR) in stratosphere in the 11-yr solar cycle are discussed,and the causes of differences between the strong and weak solar activity years are discussed.The results can be summarized as follows:Compared to the weak solar activity years,the ultraviolet radiation is stronger in the strong solar activity years,which results in the positive anomalies of OHR and NHR in whole stratosphere,and the anomalies increase with height.Ozone concentration mixing ratio shows negative(positive) anomaly in lower(upper) stratosphere,which leads to the similar pattern of both OHR and NHR,and slightly upward migration(because of the efficiency of ozone absorption in ultraviolet increases with height).As for OHR and NHR in upper stratosphere,the ultraviolet radiation plays a main role at stratopause,and ozone takes the most important part in other spaces.In this paper,the effects of ultraviolet radiation to ozone in chemistry are not discussed.In order to systematically study the influence of solar cycle on stratosphere,it needs to use chemical climate model for more detail simulation analysis.