The amount of air being greater in this direction, why is the atmosphere near the horizon whiter (paler) instead of red, orange like at sunset and sunrise?

However, in the same lecture we learned that clouds do have a positive feedback, which means (in my opinion), that by increasing temperature we have an increased amount of net radiation to earth. How is this to be understood? Does it mean that higher temperature gives rise to less clouds and therefore more net radiation?

Somehow, this appears not very intuitive, because on the one hand clouds are "good for cooling", on the other hand they have positive feedback, which is "worse for cooling". Is there a way to understand this "tradeoff" on a pure qualitative level?

I know, that clouds are quite complex and not well understood, but maybe there is a convincing explanation for that "discrepancy".

[1] https://journals.ametsoc.org/view/journals/clim/31/2/jcli-d-17-0208.1.xml

我正试图估计云层向下的长波强迫。我有入射短波辐射的直接和扩散成分的原位测量，我也有大气顶部入射短波通量(来自重新分析)。在我的场景中，云层覆盖率为100%，但其厚度未知，尽管我有温度/压力/湿度的无线电探空仪剖面。我的理论是，漫射:直接辐射的比率越高，云层就越厚。此外，与入射辐射相比，全局(直接+扩散)短波辐射越少，它就越厚。如果我知道入射的短波通量，以及流出的短波通量，我就可以把剩余的能量分成吸收的和反射的——我能在一些假设下估计出有多少能量变成了长波并发射下来吗?我特别想的是我可以用温度曲线吗?< / p >

Clearly this assumption would neglect the upward longwave power from the ground that is re-emmitted downwards from the cloud deck.

我读过关于固定砧温(FAT)假设，想知道为什么辐射冷却随着水蒸气混合比例的降低而降低。这难道不是与事实相反吗?水蒸汽是一种温室气体，因为它吸收LW辐射。那么它如何让大气降温呢?

最诚挚的问候Jan

我试图找到和使用涉及总云量%的数据。我已经从NCEI/NOAA下载了数据，特别是这里，我是这样绘制的:

import xarray as xr import numpy as np import matplotlib。Pyplot作为PLT import pygrib import cartopy。CRS作为CCRS进口cartopy。加载数据集ForecastTestDate。grb2 # atmosphereSingleLayer级别的过滤ds=xr.open_dataset('gfs_3_20220402_0000_000。grb2'， engine='cfgrib'， filter_by_keys={'stepType': 'instant'， 'typeOfLevel': 'atmosphere'}) #显示级别信息ds #tcc是大气的数据变量之一#tcc =总云量图，ax=plt.subplots() im=ax.imshow(ds.tcc) fig.colorbar(im, orientation='vertical') plt.show() 

我得到这个图:

显然这是很多云，比在同一天的缩放地球上显示的要多得多。我假设总云量%是颠倒的?这是常见的做法和/或将是相同的其他数据集从同一数据库?< / p >

高压系统通常与稳定的大气条件有关，云层很少或没有云层，但由于云层很少，这不是打开了海洋/地面的水分蒸发，然后冷凝形成云吗?我知道还有其他形式的云形成，比如下沉或锋面隆起，但在珀斯这里，有些日子非常安静，最近没有任何锋面。例如今天(2021年12月27日)，天气非常安静，但温度已经达到40°C。前两天，气温也长时间达到45°C，天空晴朗。我附近没有感觉到什么风，也没有下沉气流。< / p >

Today, there has been altostratus, altocumulus and cirrus clouds. Most of the clouds are isolated but some have formed extensive 'clumps' of cloud coverage with other clouds. So despite the high pressure system is it possible for there to be a decent amount of cloud generation? Can the ocean evaporate despite there being descending air?

意外¹我结束在字节日报页面照片2013,part 1。2013年1月9日，fishwrecked.com网站发布了一张图片，图片说明上写着:白色的大陆架云覆盖着沙尘暴(haboob)带来的棕色尘土，它穿过西澳大利亚海岸昂斯洛附近的印度洋。

Haboob在维基百科中是这样描述的:

Haboob(阿拉伯语:هَبوب，罗马语:hab3b, lit. '爆破/漂移')是一种由大气重力流携带的强烈沙尘暴，也被称为天气锋。<强>哈布在世界各地的旱地地区经常发生。< / p >

Question(s):

1. Is it rare or unusual for haboobs to travel across the Indian Ocean or other oceans?
2. Is it rarer or more unusual still for shelf clouds to appear over them?
3. What conditions are necessary to bring all of this about?

Video links from the Wikipedia article:

• YouTube: Arizona Haboob!
• Vimeo: The Phoenix Haboob of July 5th, 2011

¹I was doing a reverse image search looking for a larger size of the photo of Earth, Venus and Mars amidst the rings of Saturn when Cassini was in Saturn's shadow, and ended up on this page.

当我开始探索GOES云层的卫星图像(例如this)，我注意到云可以从"羽状物"也就是说，大的云有时可以由一个或多个非常小的点翻滚而成。例如，这张动图是由2021年6月13日GOES-East geoocolor带数据创建的:

我没有看过大量的数据，但我注意到这种效应非常普遍，经常在美国东南部、中美洲、加勒比海和大西洋中部的墨西哥湾流上空看到。换句话说，就是温暖潮湿的地方。

我的问题是:当云以这种方式形成时，为什么它们不在更大的区域产生——是什么使这些特定的“云源点”;特别的东西吗?而当“云源指向”;do形成，是什么使它们(通常)局限于小区域——是什么使这些小成核点(通常)在面积增长时保持稳定?< / p >

一些云正在树上方经过。我只是想知道这是不是一个经常发生的自然场景。云层如此接近地表的原因是什么?< / p >

Edit: My current location is 25 degrees N and 80 degrees E. it's better to call fog but they weren't stationary they were flowing quite fast from east-north to south-west. I'm attaching a couple of pictures. In the picture, the clouds are passing through that tower. Few more things to add, I'm living in the middle of the city, not in the mountains where this scenery might be seen very often. What I want is an explanation of these clouds? How they are flowing so near?

我看到卷积云在前面逐渐消失，后面有一堆卷层云。然而，我被告知，卷积云是在上层大气不稳定时出现的，而卷层云是在大气稳定时出现的，所以把两者放在一起看会让人困惑

这是什么原因?< / p >

我在网上看到科学证明花粉颗粒可以引发云的形成，这是真的吗?如果是真的，这是否意味着没有花粉颗粒的作用就不能形成云?< / p >

Is it scientifically proven that some clouds can be formed without a pollen particle's role?

这是关于开尔文勋爵对克劳修斯-克拉珀龙方程所作的“下降曲率”修正。< / p >

So, the idea is that, during large scale nucleation of water vapour into cloud droplets, the equilibrium vapour pressure over a droplet of radius r, is given by $$e_s^{\ curved}(r) = e_s(\infty)*e^{\frac{2\sigma}{\rho_w R_vTr}}$$ where, T = temperature, $R_v$ is gas constant for water vapour, $\rho_w$ is density of drop, $\sigma$ is Surface tension, and $e_s(\infty)$ is the equilibrium vapour pressure over a plain surface at temp T.

In order to derive this equation, we used the Gibbs Free Energy, and calculated that for this drop formation process, $\Delta G = - R_v T ln(\frac{e}{e_s}) \rho_w \frac{4}{3} \pi r^3 + \sigma 4 \pi r^2$

Now, when $e>e_s$, then the graph of $\Delta G$ vs r, initially increases up to a critical radius R and then decreases as shown:

$\Delta G$ vs r, S=e/e_s" />

Then, to find the equilibrium condition, we said that The drop is in equilibrium with the surrounding when the radius = R, since the slope of $\Delta G$ wrt r is 0 at r = R

However, I feel that the equilibrium condition arises for the radius r, for which, $\Delta G$ = 0. This interpretation does affect the final formula much. It just replaces the "2" with a "3".

Q: Which one of these interpretations is correct and why? Why is the other interpretation incorrect?

Kelvin's Equation

A sample Derivation - A similar derivation is seen in the book "Atmospheric Science - by Wallace and Hobbs"

问题:
虹膜效应是否存在科学共识，是正反馈还是负反馈机制?如果有，你能不能参考一下最近的出版物?< / p >

Background:
In 2001 Lindzen et. al. published this: Does the Earth Have an Adaptive Infrared Iris? They propose that current climate models (back in 2001) may underestimate the influence of a negative cloud feedback which today is called the iris effect (negative feedback: feedback that reduces an initial warming).

In brief, the iris effect is proposed to work as follows: A global warming will lead to an enhanced tropical circulation and thus lead to more subsiding air in the subtropics. The subsiding air will lead to fewer (cirrus) clouds and thus, allows outgoing long wave radiation to evade to space. Therefore, temperatures will decrease.

Own findings:
I did a little research myself which leads me to think that there is no consensus whether the feedback is positive or negative but there are many studies that at least hint the existence of the iris effect. For example I found this: "The decrease of anvil coverage with warming can be associated with both an increase in the outgoing long-wave radiation and a decrease in planetary albedo." - Saint-Lu et. al., 2020,
and this: Mauritsen, Stevens, 2015.
My hope is, however, that there is someone with more detailed knowledge who can help me. Sorry in advance if this question is too broad and "unspecific".

Please keep in mind that my question addresses the iris effect only. I'm aware that the effect of clouds on radiation is a highly active are of research. See e.g. IPCC on clouds and aerosols.

云是否可以<强>静止相对于地面?由于某种原因(经验，逻辑?)在我看来，这种情况是不可能的。我读到静止锋被定义为两个气团，这样

两个气团都不足以在地面上以至少5节(约6英里每小时或约9公里每小时)的速度推进到另一个

但这不是直接指云的速度，也不是讨论速度等于0的特定情况。

有透镜状云，它们被定义为静止的，但我不清楚这种静止是严格的(每小时0节)还是相对于“正常”的非常低的速度。云。< / p >

Anyone can provide insights on this?

我正在努力通过这篇论文:http://downloads.hindawi.com/journals/amete/2017/8707234.pdf

方程10和11需要冰水含量。我在GFS grib2文件变量中找不到。是我错过了吗，还是可以从现有的信息中推导出来。现在我有压强，温度和相对湿度

问题 GOES-16图像上的阳光是从东方来的吗?显示的是可见光图像，所以在夜间地区，地球看起来很暗，在白天地区，地球稍微亮一点，云是最亮的。我们可以用热红外卫星图像对云和天气进行24小时成像。下面是日本和澳大利亚中午的热红外图像。我本以为云顶是冷的，内陆是热的，但事实恰恰相反!< / p >

• The clouds are nearly white
• Central Australia is nearly black
• The ocean and all of the Asian continent are dull, almost featureless gray; if there weren't a superimposed outline it might be hard to even tell where the water ends and the land begins in some places.

Why is this? What's going on?

Himawari-8 IR1 image from Central Weather Bureau click for full size

是否存在一种物理定律可以抑制地面云的形成?住在英国，我知道地面上偶尔会出现雾，通常持续不超过几个小时，据我们所知，其他星球上可能也是这样，但这不是上述天体上的正常状态

云的状态，它只能是三种状态之一，固体、液体或气体。哪一种是云?< / p >

我试图用我的气象站温度/湿度的计算来估计云底高度，通过计算这两个变量，我可以得到估计的云底高度，但现在让我困惑的是不同高度的逆温层和温度。我知道grib和grib2文件包含这些数据，但我似乎无法弄清楚如何在Java中拉这些数据，即使我尝试了每一个可能的库。

有没有其他方法可以通过使用一些API来准确估计cloudbase级别，这些API为给定的纬度和经度提供了高度的温度

来自NWCSAF的云液态水路径。来源:NWCSAF。< / p >

The Algorithm Theoretical Baseline Document (ATBD; PDF, 5.9 MB) divides the full disc into the illumination regimes night, twilight, and daytime by their solar elevation, defining daylight as a solar elevation of larger than 10° (ATBD, Table 3 on Page 14). In the same document, §5.2.1.2.4 describes products only calculated in daytime conditions, including the LWP pictured above. But in the image, the retrieval appears to only include elevation angles larger than around 20° (at noon UTC, near the prime meridian, it reaches about 48°N).

Why do the data appear not to extend to solar elevation angles down to 10° such as documented, but rather truncate at around 20°?

为什么云形成一块“桌布”，完全适合南非开普敦附近的桌山山顶?桌面的某些东西使云完全适合它。厚度光滑均匀，粗略估计大约有十米厚