天气预报模型在高温或低温时更准确吗?-地江南体育网页版球科学堆栈交换江南电子竞技平台 最近30个来自www.hoelymoley.com 2023 - 04 - 11 - t00:25:59z //www.hoelymoley.com/feeds/question/12977 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/12977 11 天气预报模型在高温或低温时更准确吗? user11318 //www.hoelymoley.com/users/0 2017 - 12 - 28 - t22:55:44z 2018 - 11 - 02 - t02:00:36z 前几天我们当天的低温比我们预测的最低温度低10华氏度。我以前在冬天就注意到这一点,特别是当气温开始低于0华氏度(-18摄氏度)时,这让我想知道用于预测高温和低温的模型是否不同,如果是这样的话,哪个模型确实更准确?相反,如果使用相同的模型,对于高温和低温是否同样准确?

我能够找到达特茅斯学院的一个学生项目,该项目比较了来自15个不同美国城市的数据的三个五年(1970- 4,1980 - 4,1990 -4)的预测高温和低温的统计分析,这些数据代表了不同的影响,如纬度、水和陆地的影响。这个包含5269条记录的数据集的一个发现是,夏季的预测比秋季和冬季更准确。这似乎暗示,至少在季节性的基础上,温暖的温度比寒冷的温度预测得更准确。我希望有更多的信息可以在没有季节偏见的情况下证实或否定这一结论。< / p >

//www.hoelymoley.com/questions/12977/-/13038#13038 3 天气预报模型在高温或低温时更准确吗? 泰德 //www.hoelymoley.com/users/11931 2018 - 01 - 05 - t15:42:18z 2018 - 01 - 05 - t15:42:18z 你可能看到的问题是由于天气行业如何计算当天的低温。他们使用的时间段是从当天晚上7点到第二天早上7点。听起来很荒谬?我也是,你们自己可以很容易地观察到。去intellicast这样的网站,它会显示10天的天气预报,它还会以曲线图的形式显示温度。你可以看到,当天的低点预测经常是错误的——它是第二天的低点 //www.hoelymoley.com/questions/12977/-/14063#14063 1 天气预报模型在高温或低温时更准确吗? 卢卡斯 //www.hoelymoley.com/users/3419 2018 - 05 - 05 - t21:11:14z 2018 - 05 - 05 - t21:11:14z 有两种方法来回答你的问题:第一种是通过验证历史预测数据(计算与观测到的温度的差异),并研究这些误差的温度依赖性。这当然是可行的-但在这种情况下,Stackexchange不是。< / p >

So I suppose you refer to a general, more physically interpretable explanation what the difference in forecasting higher or lower temperatures is.

Even though it makes a difference for physical processes like radiation and evaporation if temperatures are high or low, the characteristics stay the same - more explicitly said:

Temperature differences matter more than absolute temperatures!

For example:

  • The net radiation (budget) is proportional to the difference of soil and atmospheric temperature (each to the fourth power).

  • Deeper layers of soil keep the surface warm by transporting heat (also proportional to the temperature difference).

  • and so on...

But there is a significant difference in the active physical processes: At daytime (Tmax), the near surface air is (mostly) coupled to the temperature of higher layers of air by turbulence. On a sunny summerday, the surface air can not get significantly warmer than the air above because if it gets warmer, the air rises and cooler air from above cools the surface layer. In this way, the surface air temperature is 'tied down' so that it can not reach extrordinary temperatures without also heating up a say 1500 m boundary layer of air.

If the surface air is cooler than the air above it gets decoupled from the temperatures above - turbulence is reduced, and theoretically the temperatures could drop a looong way down, until the incoming (longwave) radiation from the atmosphere (say hi to greenhouse gases) stops this temperature drop. The equilibrium temperature depends mostly on the amount of water vapor above our heads -> warmer in the tropics, cooler nights in polar regions. But the equilibrium is practically never reached. In most cases it is a dynamic thing with ground heat flux and sporadic wind gusts - which are of very local effect.

Conclusion

Comparing these two cases one can see that the Tmax is more homogenously distributed in space because it mostly depends on the airmass. Minimum temperatures can be very different even for close locations because it really depends on your surrounding: trees, buildings, ridges. You can see the lowest Tmin at high altitude locations which are not exposed to wind gusts (sinkholes) which are covered by snow (isolated from soil heat).

So by analyzing a forecast error dataset, you would most likely see that Tmax are more accurately forecast.

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