2016年经济学人 天气预报 欧洲人比美国人更擅长预测天气(下)

（单词翻译）

During its three weeks of operation, the new GFS remained outclassed. On a standard measure—predicting the altitude at which the atmospheric¹ pressure is half as great as at sea level—it still trails the ECMWF model.

全球预报系统投入运行的三周时间里，其预报质量远优于欧洲中期天气预报中心。但在一项对某纬度大气压强是海平面一半的标准测试中，全球预报系统仍落后于欧洲中期天气预报中心.

Nonetheless, the GFS's strong showing during January's nor'easter offers solace² to critics who feared America would never catch up with Europe in matters meteorological. Weather forecasting is fiendishly complex, and improvements tend to arise not from great leaps forward but rather an accumulation of incremental³ advances.

之前批评家们担心美国在气象预报方面永远也赶不上欧洲，但是全球预报系统在1月份对暴风雪东北锋面的准确预测给予了他们一些安慰。预报天气是件极其复杂的事情，要想提高预测的准确性可不能一蹴而就而要靠慢慢积累。

The ECMWF's most obvious advantage has been in raw computing⁴ power. Its Cray XC30 supercomputer can perform up to 2 quadrillion calculations a second, about ten times more than the GFS hardware before the recent upgrade. As a result, it carves up the Earth's atmosphere into svelte⁵ cells 16km square and 137 layers deep, compared with a bulky 27km and a mere⁶ 64 layers for the old GFS. The ECMWF's computing muscle also lets it start its projections⁷ with a replay of the past 12 hours of weather, using 40m data points derived⁸ from observations collected by ground stations, aeroplanes, balloons and satellites. In contrast, the GFS begins with a snapshot of a single moment.

欧洲中期天气预报中心的强势之处在于它那了得的运算能力。该气象中心拥有一台Cray XC30型超级电脑，一秒内就能运算2万亿次，其运算能力是全球预报系统硬件升级前的十倍多。这台计算机能把地球大气层整齐地分割为面积为16平方公里的若干小块，且把每块做137层分层，而升级前的全球预报系统只能做27平方公里和137层的块层分割。借助其厉害的运算能力，欧洲中期天气预报中心能对过去12小时的气象云图做回放，从而使其天气预报更为准确。云图回放时计算机要处理4000万个数据点，这些数据都是从地面观测站点，气象飞机，气球及气象卫星收集获得的。相较之下，美国的全球预报系统只能对某一特定时刻做云图拍照，进而分析预测。

The ECMWF also deserves credit for deploying⁹ its computational force wisely. The centre was a pioneer in using satellites to fill gaps in the data over the oceans, and in developing “ensemble forecasts” that generate a range of outcomes by employing slightly different starting conditions to produce multiple predictions. Its current model runs 52 such forecasts in parallel, each with a probability assigned to it.

欧洲中期天气预报中心对其强大的运算能力使用分布得当亦值称赞。该中心在运用卫星进行气象观测，弥补海洋气象数据不足方面处于领先地位；此外，它还开发出一套名为“系集预报”的模型，即通过利用气象起始状况的细微不同来得出多项预测从而得到多个预报结果。欧洲中期天气预报中心现有的这个模型能同时进行52项这样的气象预测，每个预测都会得出一个预报结果。

Weather forecasters in America have full access to the ECMWF's model. However, the United States still has good reason not to free-ride on the Europeans' work. Private American firms have to pay for it, and the ECMWF is unlikely to develop regional or local models focused specifically on America. Moreover, giving the ECMWF a worthy¹⁰ competitor would probably lead to better forecasts overall.

美国的气象预报人员具有使用欧洲中期天气预报中心该模型的全部权限。但是美国还是找出了不搭便车的理由。一来美国私人公司要付费使用该模型，二来是欧洲中期天气预报中心也不可能针对美国开发出一套区域性更强的模型，三来欧洲中期天气预报中心是个劲敌，与之竞争或许能全面促进美国天气预报的发展。

The new GFS has certainly narrowed the gap. Its resolution is now 13km, though it still has only 64 layers. By November it is expected to run on a faster computer than the ECMWF's. It could be in line for further upgrades if the new, Republican Congress reintroduces the Weather Forecasting Improvement Act proposed last year—though the party's global-warming sceptics are likely to demand that much of the additional $120m a year the bill offered be taken away from research on climate change.

全球预报系统升级后着实缩小了与欧洲中期天气预报中心的差距。虽然该系统大气分层能力还只能分出64层，但现如今它的气象分辨率已经能达到13千米。今年11月，全球预报系统有望将换装比欧洲中期天气预报中心运行速度更快的超级电脑。如今美国国会已是共和党人的主场了，如果他们能重新采纳去年递交的“气象预报完善法案”，那全球预报系统有望得到进一步升级。该法案要求每年给气候研究增加1200万美元的经费，虽然共和党内的“全球变暖”怀疑者们可能会要求大幅裁减这笔资金。

According to Cliff Mass, a professor of meteorology at the University of Washington, more money will not be enough to catch up with the Europeans. America, he says, must integrate its separate research and forecasting divisions, and include more contributions from non-government experts. Compared with pushing through cultural change in large public bureaucracies, predicting the weather is easy.

华盛顿大学气象学教授Cliff Mass称，即使美国投入再多的钱其天气预报的能力也无法赶上欧洲人。他说美国要想在这方面获得实质性的提高不仅得把其气候专项研究和各预报部门综合起来，还得广纳民间气候专家的建议。较之在官场推行政治文化气息变革，预测天气真算得上是简单的了。