民用航空气象地面观测规范第15章 卫星云图的基本知识

民用航空气象地面观测规范第15章 卫星云图的基本知识 第十五章 卫星云图的基本知识 第一节 极地轨道气象卫星与静止气象卫星 一、气象卫星的概况 按照气象卫星的轨道倾角可以将卫星轨道分为前进轨道、后退轨道、赤道轨道和极地轨道四种。 极地轨道气象卫星是指太阳同步极地轨道气象卫星，卫星的轨道平面与太阳始终保持固定的取向。它绕地球极地轨道运行而与太阳同步，运行高度一般在1000千米左右，运行周期约两小时。由于太阳同步卫星的轨道近于圆形，轨道的预告、资料的接收定位处理十分方便;太阳同步轨道卫星可以观测全球，尤其是可以观测到极地地区;在观测时有合适的照明，可以得到稳定的太阳能，保障卫星正常工作。虽然太阳同步卫星可以获取全球资料，但是时间分辨率低;相临两条轨道的观测资料不是同一时刻的，需要进行同化。 静止气象卫星是指地球同步轨道气象卫星。它在地球赤道上空静止轨道运行，与地球处于相对静止状态。静止气象卫星的高度高，视野广阔，运行高度约35860千米，每隔30分钟或1小时，就可对大气层完成一次近1亿7千万平方千米面积的观测;可以监视天气云系的连续变化，特别是生命史短、变化快的中小尺度灾害性天气系统。静止气象卫星的缺点是不能观测南北极区，同时对卫星观测仪器的要求高。 1988年9月7日我国发射了第一颗近极地太阳同步轨道气象卫星，命名为FY-1A。2002年5月15日发射了第四颗近极地太阳同步轨道卫星，命名为FY-1D。1997年6月10日我国发射了第一颗静止气象卫星，命名为FY-2A。2004年10月19日，我国成功发射了第三颗静止气象卫星，命名为FY-2C。 二、卫星探测的特点 (一)气象卫星在固定轨道上对地球大气进行观测 气象卫星一旦进入轨道，便只能在固定的轨道上观测地球大气。当卫星选用一定的轨道，则观测范围和区域就一定，所以对于一定的观测目的，轨道的选择是十分重要的。 (二)气象卫星可实现全球和大范围观测 气象卫星在离地面几百千米到几万千米的宇宙空间，它不受国界和地理条件的限制，可对地球大气进行大范围的观测。如地球静止气象卫星一般位于3.6万千米高空对某一固定区域进行观测，观测面积可达地球面积的1/3。海洋、沙漠和members from key minority outreach, promote a comprehensive strictly administering the party into the branches, put it into every party member, give full play to each party organization fight fortress function, each the exemplary vanguard role of party members. Is to promote the inner-party education extend from the concentrated education to regular education, in the regular education efforts, real party ideology in the all party members and the party's construction through system. Is to boost the spirit of all party members, education guide all members of the party in their respective work positions, responsible and dependable officer, make contributions. Therefore, we must from the height of political and global, fully aware of "two" learning the importance of education, put "two" education as a major political task and practice well. All members to active participation, really into, in "learn, and do, and modified, and promoting" upper and lower really Kung Fu, effective put thought and action unified to XI General Secretary of important indicates spirit up, unified to Central and provincial of decision deployment up, solid do learning education the work, effective do good accountability, caught in place, see effectiveness, condensed up officer venture, and promoted water the work of powerful power. Second, accurately grasp the "two" educational focus ... Marxist positions, knowing that good talk show a strong belief in pursuit, history as spirit, sincere feelings for the people, pragmatic style of thinking, enhance the scientific level of the work, and to better promote our work. In terms of learning methods, units of the party organization, the party branch in accordance with the implementation plan, organization members planned and subtopics to learn to combine 第十五章 卫星云图的基本知识 高原地区都可以从卫星探测获取气象资料，从而深入了解全球大气活动; (三)在空间自上而下观测 气象卫星在空间自上而下观测地球大气，这与地面观测是不同的。如对云的观测，卫星观测到的是云顶的特征。在有几层云时，卫星首先观测到的是高云;若高云很薄，则可透过高云看到中低云;如果高云很厚就无法看到中低云。 (四)气象卫星采用遥感探测方式 气象卫星采用遥感的方法获取大气和地面目标物的特性。遥感探测具有观测速度快、项目多、信息量大和测量系统不干扰被测目标物，以及资料代表性好等优点。 (五)有利于新技术的发展和推广应用 第二节 卫星观测的基本原理 一、可见光云图的基本原理 可见光云图(图15-1)是卫星接受地面和云区反射的太阳辐射转化而得到的图像。可见光图上的色调决定于反射太阳辐射的强度(与物体的反照率和太阳高度角有关)。反照率越大，色调越白;反照率越小，色调越暗。太阳高度角越大，光照条件越好，卫星接受到的反射太阳辐射也越大，否则越小。云区越厚，色调越白。但是可见光云图只有在白天才能收到。 图15,1 2002年8月4日16:30(北京时)可见光云图 二、红外云图的基本原理 卫星接受云区和地面本身的红外辐射总量，用图像表示出来，即为红外云图(例图15-2)。它反映了地面和云面的红外辐射或亮度温度分布。在红外云图上，色调越暗，温度越高，卫星接收到的红外辐射越大;色调越浅，温度越低，辐射越小。 members from key minority outreach, promote a comprehensive strictly administering the party into the branches, put it into eve- 202 - ry party member, give full play to each party organization fight fortress function, each the exemplary vanguard role of party members. Is to promote the inner-party education extend from the concentrated education to regular education, in the regular education efforts, real party ideology in the all party members and the party's construction through system. Is to boost the spirit of all party members, education guide all members of the party in their respective work positions, responsible and dependable officer, make contributions. Therefore, we must from the height of political and global, fully aware of "two" learning the importance of education, put "two" education as a major political task and practice well. All members to active participation, really into, in "learn, and do, and modified, and promoting" upper and lower really Kung Fu, effective put thought and action unified to XI General Secretary of important indicates spirit up, unified to Central and provincial of decision deployment up, solid do learning education the work, effective do good accountability, caught in place, see effectiveness, condensed up officer venture, and promoted water the work of powerful power. Second, accurately grasp the "two" educational focus ... Marxist positions, knowing that good talk show a strong belief in pursuit, history as spirit, sincere feelings for the people, pragmatic style of thinking, enhance the scientific level of the work, and to better promote our work. In terms of learning methods, units of the party organization, the party branch in accordance with the implementation plan, organization members planned and subtopics to learn to combine 第十五章 卫星云图的基本知识 图15,2 2002年8月4日16:30(北京时)红外云图 三、水汽云图的基本原理 卫星接收以6.7微米为中心的水汽强吸收带发出的辐射，用图像表示出来，即为水汽云图(例图15-3)。水汽图中，色调越白，水汽含量越高;色调越暗，水汽含量越低。 图15,3 2002年8月4日16:30(北京时)水汽云图 四、可见光云图和红外云图的比较 可见光云图上物像的色调决定于其反照率和太阳高度角,红外云图上物像的色调决定于它的温度,所以这两种云图,有一些外貌上相差很大,但也有些十分相似。表15-1给出了这两种云和地表色调的特征比较。该表中各物像所对应的色调，只是概念性的，由于决定物像的因素很多，所以如仅仅按照表中的色调判别是不够的。 表15,1 可见光云图与红外云图的比较图表 红 夏季沙漠黑 太阳耀斑 干土壤 暖湿地 暖海洋 外 (白) members from key minority outreach, promote a comprehensive strictly administering the party into the branches, put it into eve- 203 - ry party member, give full play to each party organization fight fortress function, each the exemplary vanguard role of party members. Is to promote the inner-party education extend from the concentrated education to regular education, in the regular education efforts, real party ideology in the all party members and the party's construction through system. Is to boost the spirit of all party members, education guide all members of the party in their respective work positions, responsible and dependable officer, make contributions. Therefore, we must from the height of political and global, fully aware of "two" learning the importance of education, put "two" education as a major political task and practice well. All members to active participation, really into, in "learn, and do, and modified, and promoting" upper and lower really Kung Fu, effective put thought and action unified to XI General Secretary of important indicates spirit up, unified to Central and provincial of decision deployment up, solid do learning education the work, effective do good accountability, caught in place, see effectiveness, condensed up officer venture, and promoted water the work of powerful power. Second, accurately grasp the "two" educational focus ... Marxist positions, knowing that good talk show a strong belief in pursuit, history as spirit, sincere feelings for the people, pragmatic style of thinking, enhance the scientific level of the work, and to better promote our work. In terms of learning methods, units of the party organization, the party branch in accordance with the implementation plan, organization members planned and subtopics to learn to combine 第十五章 卫星云图的基本知识 云 深 沙漠(白) 晴天积云 湿土壤 图 灰 层 沙漠(夜间) 层云积 晴天积云 纤维状卷云 青藏高原 高山森 灰 (厚) 云 卷层云(薄) 林 雾(厚) 淡高层云(厚) 纤维状卷云 高层高层云 冷海洋 灰 浓积云 (薄) 密卷云，多层云 单独厚卷云 卷云 单独薄卷宇宙空 积雨云，卷云砧 卷层云 消失中的卷云 间 白 高山积雪，极地冰云砧 雪 白 淡灰 灰 深灰 黑 可 见 光 云 图 第三节 云图的识别 一、识别云图的基本判据 在卫星云图上，云的识别可根据以下六个基本特征来判别:结构型式、范围大小、边界形状、色调、暗影和纹理。 (一)结构型式 结构型式是指卫星云图上不同明暗程度的物像点的分布样式。这些物像点或是散乱分布，或是有组织分布，组成一定的形状。在云图上云的结构型式有带状、涡旋状、块状、细胞状和波状等。例如:气旋和台风云系是涡旋状结构;锋面、急流云系常表现为带状;孤立的对流云常表现为豆状或块状。 (二)范围大小 卫星云图上云的类型不同，范围也不同。如气旋、锋面云系和急流云系往往有几千公里，而一般的对流单体仅仅有十几到几十公里。因此云图中云区的范围大小可用来区分云单体、不同尺度云系，结合型式可推断云形成的物理过程;根据云区的大小，可识别出孤立的单体和云系。 (三)边界形状 云图上云的边界有的呈直线形、圆形、扇形;有的呈气旋性弯曲、也有呈反气旋性弯曲;有的云(如层云和雾)的边界十分整齐光滑，有的云(积云和浓积云)的边界则很不整齐。不同云的边界有不同的特征，所以云的边界形状是识别云的重要依据之一。 members from key minority outreach, promote a comprehensive strictly administering the party into the branches, put it into eve- 204 - ry party member, give full play to each party organization fight fortress function, each the exemplary vanguard role of party members. Is to promote the inner-party education extend from the concentrated education to regular education, in the regular education efforts, real party ideology in the all party members and the party's construction through system. Is to boost the spirit of all party members, education guide all members of the party in their respective work positions, responsible and dependable officer, make contributions. Therefore, we must from the height of political and global, fully aware of "two" learning the importance of education, put "two" education as a major political task and practice well. All members to active participation, really into, in "learn, and do, and modified, and promoting" upper and lower really Kung Fu, effective put thought and action unified to XI General Secretary of important indicates spirit up, unified to Central and provincial of decision deployment up, solid do learning education the work, effective do good accountability, caught in place, see effectiveness, condensed up officer venture, and promoted water the work of powerful power. Second, accurately grasp the "two" educational focus ... Marxist positions, knowing that good talk show a strong belief in pursuit, history as spirit, sincere feelings for the people, pragmatic style of thinking, enhance the scientific level of the work, and to better promote our work. In terms of learning methods, units of the party organization, the party branch in accordance with the implementation plan, organization members planned and subtopics to learn to combine 第十五章 卫星云图的基本知识 (四)色调 色调有时也称亮度或灰度，它是指云图上的物像的明暗程度。可见光图上的色调与物体的反照率及太阳高度角有关。云的厚度越厚，反照率越大，色调越白。 在红外云图上，色调表示辐射面温度的高低。根据色调，可分析地表温度的高低和高、中、低云的分布状况。色调越白，云顶就越高;反之温度越高色调越暗，云顶越低。 (五)暗影 暗影只在可见光图上出现，它是在一定太阳高度角下，高的目标物在低的目标物上的投影。根据暗影可以识别物体的相对高度及云的类别。云越厚、云顶越高，暗影越宽;暗影的宽度与太阳高度角有关，太阳高度角越低，迎太阳一侧云的色调越明亮，背太阳光一侧出现暗影。在分析暗影时要将云的裂缝与暗影分开。 (六)纹理 纹理表示了云顶表面的光滑程度。云的种类和厚度不同，云顶表面光滑度不同。如果云的纹理光滑均匀，说明云的云顶高度和厚度相差小，如层云和雾;如果云的纹理多皱纹和斑点，说明云顶高度不一，多起伏，这是积状云的特征;而纤维状是卷状云的特征。 二、几种云的简单识别 (一)卷状云 一般卷状云高度较高，温度低，较厚(薄)的卷云在红外图上通常为白(灰白)色，纹理均匀，边界多为纤维状。由冰晶组成，由于反照率低，对可见光具有透明性。所以可见光图中为深灰到浅白色，云体较薄时，可见光图中无显示。水汽图上呈白色。 在卫星云图上，卷云分为:卷层云、纤维状卷云、卷云砧和密卷云。 (二)积雨云 积雨云在卫星云图上常呈团状结构，称为云团;色调在红外、可见光或水汽云图中均为最白;初生时边界整齐光滑，发展和成熟阶段时下风方出现卷云羽;纹理在红外云图及水汽图上比较均匀，可见光图上呈多皱纹和斑点;积雨云云顶高，有暗影，但是积雨云在夏季最活跃，这时除早晚时刻，太阳高度角大，暗影并不是时时都明显。在增强红外图上，可以看到明显的回波核，此处对流强度最大。 (三)中云(高层、高积云) 在卫星云图上，由于高积云单体远小于卫星仪器的分辨率，无法将高积云与高层云区别开来，只能将高积云和高层云统称为中云。 中云在卫星云图上表现为一大片，其型式可以是涡旋状、带状、线状和逗点状;大多数中云出现在卷云下面，如果卷云下面有中云，则其色调更白一些;在 members from key minority outreach, promote a comprehensive strictly administering the party into the branches, put it into eve- 205 - ry party member, give full play to each party organization fight fortress function, each the exemplary vanguard role of party members. Is to promote the inner-party education extend from the concentrated education to regular education, in the regular education efforts, real party ideology in the all party members and the party's construction through system. Is to boost the spirit of all party members, education guide all members of the party in their respective work positions, responsible and dependable officer, make contributions. Therefore, we must from the height of political and global, fully aware of "two" learning the importance of education, put "two" education as a major political task and practice well. All members to active participation, really into, in "learn, and do, and modified, and promoting" upper and lower really Kung Fu, effective put thought and action unified to XI General Secretary of important indicates spirit up, unified to Central and provincial of decision deployment up, solid do learning education the work, effective do good accountability, caught in place, see effectiveness, condensed up officer venture, and promoted water the work of powerful power. Second, accurately grasp the "two" educational focus ... Marxist positions, knowing that good talk show a strong belief in pursuit, history as spirit, sincere feelings for the people, pragmatic style of thinking, enhance the scientific level of the work, and to better promote our work. In terms of learning methods, units of the party organization, the party branch in accordance with the implementation plan, organization members planned and subtopics to learn to combine 第十五章 卫星云图的基本知识 红外云图上，中云的色调介于高云和低云之间的中等程度灰色，对于较厚的中云色调呈浅灰色。 (四)积云、浓积云 海洋面上积云和浓积云常表现为线状、开口细胞状等结构型式;陆地丘陵山地积云和浓积云呈离散分布型式。积云浓积云无论在可见光云图还是在红外云图上，表现为多斑点、皱纹，为不均匀的纹理;边界不整齐不光滑;在可见光云图上呈白色，在红外云图上由于积云浓积云的高度参差不齐，云顶温度有差异，色调也不一致。 (五)低云 在冬季洋面冷锋后或副热带高压的东南象限，层积云常表现为球状的闭合细胞状云系;在海洋上，水汽丰富，层积云一般密蔽天空，云顶均匀，在可见光云图上呈白色，在陆地，层积云反照率低，呈断裂的、稀疏分布，表现为灰色。在红外云图上，层积云表现为深灰到灰色，可与中云区分开来。 卫星云图上层云和雾特征相似，纹理均匀，边界清晰;由于接近地面，温度相对较高，红外图中为暗灰色，而可见光中为白色。 在可见光云图上，雨层云从白到灰白不等，当太阳高度角较低时，可以在雨层云中见到纹线，通常雨层云出现于锋面云系中，在热带季风云系中也可以见到。在红外云图上雨层云表现为均匀的灰色到白色。 members from key minority outreach, promote a comprehensive strictly administering the party into the branches, put it into eve- 206 - ry party member, give full play to each party organization fight fortress function, each the exemplary vanguard role of party members. Is to promote the inner-party education extend from the concentrated education to regular education, in the regular education efforts, real party ideology in the all party members and the party's construction through system. Is to boost the spirit of all party members, education guide all members of the party in their respective work positions, responsible and dependable officer, make contributions. Therefore, we must from the height of political and global, fully aware of "two" learning the importance of education, put "two" education as a major political task and practice well. All members to active participation, really into, in "learn, and do, and modified, and promoting" upper and lower really Kung Fu, effective put thought and action unified to XI General Secretary of important indicates spirit up, unified to Central and provincial of decision deployment up, solid do learning education the work, effective do good accountability, caught in place, see effectiveness, condensed up officer venture, and promoted water the work of powerful power. Second, accurately grasp the "two" educational focus ... Marxist positions, knowing that good talk show a strong belief in pursuit, history as spirit, sincere feelings for the people, pragmatic style of thinking, enhance the scientific level of the work, and to better promote our work. In terms of learning methods, units of the party organization, the party branch in accordance with the implementation plan, organization members planned and subtopics to learn to combine