Bolometric Solar Imaging

辐射热太阳成像

• 批准号: 0440787
• 负责人: David Rust
• 金额: $ 20万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0440787&HistoricalAwards=false
• 关键词: Bolometric; Solar; Imaging

This proposal is to design, build, and launch the Solar Bolometric Imager (SBI) and a Multi-Spectral Imager (MSI) on the Long Duration Balloon (LDB) from McMurdo during the austral summer of 2006-2007. The instruments will provide bolometric (i.e., wavelength-integrated light) and color temperature images of the Sun, which will be aimed to understand better sources of the solar irradiance variation and the corresponding effects on global terrestrial climate change. The current view is that during the 11-year sunspot cycle the total solar irradiance varies in proportion to the changes of Sun's local magnetic fields. At the upcoming sunspot minimum (2007), SBI observations will be able to detect if there are other sources of solar irradiance variation with the least confusion by signals from the magnetic fields. The SBI is a new instrument, a new approach to studying one of the fundamental problems in solar physics. The imager uses a 30-cm diameter F/12 Dall-Kirkham telescope with uncoated mirrors, and neutral density filters to provide broadband (bolometric) sensitivity that varies only by +/-7 percent over the wavelengths from 0.28 to 2.6 microns The SBI sensor has the unique capability to record images of the solar photosphere with a flat photometric response. The sensor is an array of 320 x 240 infrared-sensitive barium strontium titanate (BST) ferroelectric elements, with a film of gold black on the surface. The film will uniformly convert all absorbed solar radiation into thermal emission detectable by the underlying BST array. MSI will provide diagnostics of solar magnetic and thermal structures while SBI assesses their radiance. Each frame from the SBI and MSI will be precisely calibrated. Bursts of 60 to 120 frames of the same scene will be co-registered and summed to increase the signal-to-noise ratio. The scenes will be mosaicked to form images with 5-arcsec resolutions over the entire Sun. Sunspots, faculae, and magnetic filed network will be identified from the MSI images. Sonic filtering of the MSI images will isolate the oscillatory signal. That signal will be used to remove oscillations from SBI averages to reduce the solar noise. The calibrated, mosaicked SBI images will be used to derive data products such as 3D plots of intensity contrast versus distance from Sun center and magnetic flux. The images and data products will be openly available via the Web. The SBI/MSI telescopes will be carried into the stratosphere by a balloon-borne gondola used in previous Antarctic programs. Scientific ballooning is an ideal educational tool because it is relatively inexpensive and quick to produce results. The science team will include experienced experimentalists and a post-doctoral associate, at least one graduate student, and several student interns. The campaign will involve many ground-based observatories and satellite-borne radiometers from several countries.

本项目计划于2006-2007年夏季在麦克默多的长时间气球上设计、建造和发射太阳辐射热成像仪（SBI）和多光谱成像仪（MSI）。这些仪器将提供热辐射测量（即，这些图像的目的是更好地了解太阳辐照度变化的来源以及对全球陆地气候变化的相应影响。目前的观点是，在11年的太阳黑子周期中，太阳总辐照度的变化与太阳局部磁场的变化成正比。在即将到来的太阳黑子极小期（2007年），SBI的观测将能够探测到是否有其他太阳辐照度变化的来源，同时最大限度地减少磁场信号的干扰。SBI是一种新的仪器，一种研究太阳物理学基本问题之一的新方法。成像仪使用直径30厘米的F/12 Dall-Kirkham望远镜，无涂层反射镜和中性密度滤光片，提供宽带（辐射热）灵敏度，在0.28至2.6微米的波长范围内变化仅为+/-7% SBI传感器具有独特的能力，可以记录太阳光球层的图像，并具有平坦的光度响应。该传感器是一个320 × 240的红外敏感钛酸锶钡（BST）铁电元件阵列，表面有一层金黑色薄膜。该薄膜将所有吸收的太阳辐射均匀地转换为可由底层BST阵列检测的热发射。MSI将提供太阳磁场和热结构的诊断，而SBI将评估它们的辐射。SBI和MSI的每个帧都将被精确校准。同一场景的60到120帧的突发将被共同配准和求和，以增加信噪比。这些场景将被镶嵌在整个太阳上，形成分辨率为5角秒的图像。太阳黑子、光斑和磁场网络将从MSI图像中识别出来。MSI图像的声波滤波将隔离振荡信号。该信号将用于消除SBI平均值的振荡，以减少太阳噪音。经校准的、镶嵌的SBI图像将被用于导出数据产品，如强度对比度与太阳中心距离和磁通量的3D图。图像和数据产品将通过网络公开提供。SBI/MSI望远镜将由以前南极计划中使用的气球携带的吊舱携带到平流层。科学热气球是一种理想的教育工具，因为它相对便宜，而且见效快。科学团队将包括经验丰富的实验人员和一名博士后助理，至少一名研究生和几名实习生。这场运动将涉及若干国家的许多地面观测站和星载辐射计。