政府机构和大多数科学家认为,2015年是有气象记录以来最温暖的一年,他们的依据是地表温度。但是阿拉巴马大学的约翰 克里斯蒂,以及研究卫星温度检测系统的亨茨维尔却认为,卫星才是检测气候变暖的更有效工具。 提到测量全球变暖的时候,指的是海报高度。 如果靠近地表测量地球的“体温”,高度大约距离地面6英尺处,温度计显示的温度比在轨卫星测量的度数要高一些。 这种差异给那些气候变化怀疑论者提供了反驳的证据。 政府机构和大多数科学家主要依靠地面测量,他们的研究表明,2015年是有气象记录以来最温暖的一年。 国家海洋局、美国航空航天局、日本和英国的气象机构以及世界气象组织都使用地面数据。科学家说这个数据具有更好的准确性和相关性。 “我们都关注我们生活的地方会发生哪些变化。这就是为什么我们要测量地表温度,这个温度是与人类生活最密切相关的,”德克萨斯科技大学气候学家凯瑟琳 海赫说。 但是那些质疑公认科学的人们(大多数都不是科学家),更倾向于采用卫星数据(自1979年开始)。卫星数据显示2015年是有记录以来第三个最热的年份。 反对主流气候科学观点的政治家,如共和党总统候选人特德 克鲁兹,特别引用了卫星测量系统和遥感系统的数据,并断言最近18年来没有出现全球变暖。还有一些科学家提出这样的主张,包括一个运行遥感系统的科学家们,他们认为地表温度是一种误导。 遥感系统高级科学家卡尔 米尔斯,在回复美联社的电子邮件中提到:“卫星不是用来测量地表变暖的。它们是测量大气层的平均温度”距离地面大约5万英尺。 米尔斯说“但是对于人类社会和环境的影响来说,地表数据更重要。” 米尔斯说,他分析的卫星数据是地表测量数据误差幅度的五倍。这是因为卫星使用了复杂的数学算法和数千位代码,将波长测量数据转化成温度读数,海赫说。 阿拉巴马大学的约翰 克里斯蒂,以及研究卫星温度检测系统的亨茨维尔,认为,卫星是检测温室气体导致气候变暖的更有效工具,因为“地表温度更容易受到其它变量的影响,这个数据不能代表气候系统的真实情况。” 克里斯蒂和米尔斯的卫星数据都显示,全球变暖开始于1980年前后,也就是刚刚用卫星开始测量温度的时候。两个卫星系统的数据显示,过去35年气候仅仅变暖了0.7度,而地表温度显示全球气温整整升高了1度。(中国科技网) 英文原文: Earth's temperature depends on where you put thermometer When it comes to measuring global warming, it's all about altitude. Temperature readings taken close to Earth's surface—about 6 feet off the ground—show a slightly warmer planet than measurements taken from on high by satellites in orbit. And that discrepancy has given ammunition to climate-change doubters. Government agencies and most scientists rely primarily on ground measurements, and they show that 2015 was the warmest year on record. The National Oceanic Atmospheric Administration, NASA, the Japanese and British meteorological agencies and the World Meteorological Organization all use ground data. It's a matter of better accuracy and relevance, scientists say. "We care about what's happening where we live. That's why ground-based temperatures are most relevant to humans," said Texas Tech climate scientist Katharine Hayhoe. But those who try to cast doubt on accepted science—most often non-scientists—prefer satellite data that goes back to 1979. And the data shows that 2015 was only the third-warmest year on record. Politicians who reject mainstream climate science, such as Republican presidential candidate Ted Cruz, especially cite one satellite measurement system, Remote Sensing Systems, in asserting that there has been no global warming for 18 years. That's a claim scientists, including the one who runs RSS, say is misleading. Carl Mears, senior scientist for Remote Sensing Systems, told The Associated Press in an email: "The satellite measurements do not measure the surface warming. They are measurements of the average temperature of thick layers of the atmosphere" about 50,000 feet off the ground. "For impacts on human society and the environment, the surface data are more important," Mears said. Mears said his analysis of his own satellite data has five times the margin of error of ground measurements. That's because satellites use complex mathematical algorithms and thousands of bits of code to translate wavelength measurements into temperature readings, Hayhoe said. Scientists routinely use ground measurements to calibrate and validate satellite information, said Marshall Shepherd, a University of Georgia meteorology professor. He and several other scientists called surface measurements "the ground truth." John Christy at the University of Alabama, Huntsville, who runs a separate satellite temperature monitoring system, said satellites are better for detecting warming from heat-trapping gases because the "surface is affected by too many other variables and doesn't represent the real mass of the climate system." Both Christy's and Mears' satellite data show that the world has warmed since about 1980, when satellites started measuring temperature. The two satellite systems show about seven-tenths of a degree of warming in the past 35 years, while ground data shows about a full degree. |






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