中尺度WRF模式在西北西部地区低层风场模拟中的应用和检验

通过WRF模式对西北地区1、4月份风速的模拟,检验了大气数值模式的模拟性能和误差大小.结果表明,WRF模式在风场模拟上具有较好的性能,在地面加热较强、增温较快、风速较大的4月份模拟效果要好于强风频发但风速较4月份小的1月份;4月份10～70 m各高度上48 h内的平均相对误差在10％以下,相关系数＞0.80,通过99％...     

1974年9月10日白光耀斑研究

本文详细分析了１９７４年９月１０日白光耀斑的光谱资料，并利用Ｎｏｎ－ＬＴＥ理论计算了它的半经验大气模型和辐射损失。由光谱测量得到：（１）连续辐射强度在巴耳末系限（３６４７）附近发生跳跃。在极大时刻，巴耳末跳跃可达约１１％；（２）该耀斑有强而宽的巴耳末谱线发射，其高项巴耳末谱线轮廓的全半宽随主量子数ｎ而变化，在８＜ｎ＜９达到极小；（３）连续辐射极大时刻同微波爆发极大相一致，比Ｈａ耀斑极大时刻提前几分钟。这三个特征很可能是Ⅰ类白光耀斑的典型特征。     

Unusually Broadened Spectral Profiles Observed in Solar Prominences

After surveying the spectra of 39 prominences observed by the Multichannel Infrared Solar Spectrograph at Purple Mountain Observatory and the 25 cm coronagraph at the Norikura Solar Observatory, we found that about 28% of them show small spatial scale (6"- 8") and short time scale (tens of seconds to a few minutes), unusual large broadening and large shift velocities in spectral lines including Hα, Hβ, Hε, Ca Ⅱ H, Ca Ⅱ K, Ca2Ⅱ 8542 A, He Ⅰ D3 and HeⅠ 10830 A. We present in detail two typical events observed respectively on 2002 May 27 and 1981 August 2. The full-width at half maximum of the widest profile of the 2001 prominence is 1.8 A for Ha and 2.9 A for He I 10830 A, while that of the 1981 prominence is 5.3 A for Hβ, 3.6 A for Ca Ⅱ K, 4.0 A for Ca Ⅱ H and 2.8 A for He Ⅰ D3. Such broadenings generally occur at a level of several-thousand kilometres above the chromosphere. Further, most of these prominences manifest a rotation of (0.4-1.35) ×10-2 rad s-1 pointing to the Sun and large line