Doug Simonian

NASA rocket launch to the Moon will be visible from NYC tonight

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A historic rocket launch will take place tonight from the NASA Wallops site in the eastern shores of Virginia. This will be first rocket launch out of the Earth from this site.

Although the best views will be in Virginia, Delaware, and Maryland, the entire NYC Metro area will still be close enough to get a great view of it. The best view is expected to be around 11:27 p.m. tonight, which is when the rocket will launch. This will be the time to look to the south.

An image illustrating the viewing scheme of the rocket, taken from the perspective of someone on the Empire State Building viewing deck. Image credit goes to universetoday.com

An image illustrating the viewing scheme of the rocket, taken from the perspective of someone on the Empire State Building viewing deck. Image credit goes to universetoday.com

Some of you may be concerned about the tall buildings obscuring the view of the rocket. However, that should not be an issue, given the close proximity of NYC. The rocket will be high enough above the horizon for all to see. Additionally, skies look to be clear tonight, making for great conditions to see the rocket.

The first sighting will be to the south, near the horizon, around fifty seconds after the launch. The rocket will then appear higher above the horizon shortly after, and then continue to get higher above the horizon, but at a slower rate (a logarithmic curve).

nyc rocket 2

An image illustrating the viewing scheme of the rocket, taken from the perspective of someone in Battery Park. Image credit goes to universetoday.com

After a few minutes, the rocket will be out of our field of view. Once again, anyone who wants to see it will need to be prepared at promptly 11:27 p.m., and look to the south!

For more detailed information on the rocket launch, check out this link. It turns out that almost all of the northeast will have some sort of view of the rocket.

Enjoy your night, everyone!

 

Doug Simonian

Could a changing climate mean more Sandy tracks?

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The effects of a changing climate on our weather have been debated for years. With each extreme weather event, more people are left wondering whether it can be attributed to climate change or not. After all, many scientists have stated that a changing climate would mean more extreme weather events. However, it is irresponsible to say that every extreme weather event can be attributed to climate change, because that would imply that there was no extreme weather before climate change began.  Remember, the weather is inherently “extreme”, and our daily averages and means are derived from extremes on both sides of the spectrum: hot and cold, wet and dry, and windy and calm. We do not hover around our average highs and lows every single day.

That being said, there may be a link to a changing climate and more extreme weather phenomena, such as the extreme track that “Sandy” took in late October, 2012 — which devastated the lives of many people, and with whom many shoreline communities are still recovering from.

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Doug Simonian

Arctic Sea Ice Loss Not Nearly as Bad as Last Year

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Global climate change has been a pretty hot topic in the world of meteorology and climatology for quite some time now. Skeptics and pro AGW (Anthropogenic — meaning human as opposed to natural — Global Warming) have raged on and on. One of the main components that people like to look at to track the degree of warming is the amount of Arctic Sea Ice loss. As the calendar slides through August and into September, we get closer and closer to the minimum ice extent for the year, before recovering for the fall and winter. Arctic Sea Ice has really declined in the past several years — potentially due to AGW, as the amount of loss last year was absolutely staggering. In fact, the entire 2007-2012 period saw unprecedentedly low levels of Arctic Sea Ice that led many to become quite worried about this being the new normal.

Most global climate simulations indicate that the area of greatest warming would be in the Arctic — mainly because it is easier to heat something that is cold than what is hot. Decreasing the amount of Arctic Sea Ice could lead to lots of devastating climate feedbacks on the Earth’s system, such as a lot less radiation being deflected back into space, and further yielding warming. This is because ice and snow have a higher albedo (ability to reflect heat radiation back into space) than water. Thus, a warming arctic –> more water and less ice & snow –> lower albedo in the arctic –> less heat radiation is reflected back into space (and is instead absorbed by the water) –> warming arctic. This means that the feedback helps to amplify the original effect of warming the arctic, without increasing the warming effect itself.

When the Artic regions are quite warm, this is obviously bad for many ecosystems alike. But it would also greatly alter the weather patterns in that it would change the jet stream configuration, since if you are warming the Arctic a lot more than the equatorial latitudes, you are decreasing the temperature gradient between the two, which is what fuels the jet stream to begin with. There are a lot more climate feedbacks and such, but to save time, we won’t get into that for now.

Arctic Sea Ice extent from this year (red) is much higher than from last year (black). However, it is still well below the 1979-2006 averages.

Figure 1: Arctic Sea Ice extent from this year (red) is much higher than from last year (black). However, it is still well below the 1979-2006 averages.

Arctic Sea Ice can be measured in two ways: ice extent and ice area. The National Snow and Ice Data Center explains the differences well here, but essentially, the analogy is swiss cheese. Extent would be the distance from the edges of the cheese and all of the space inside the edges — so it does not include the holes, whereas the area takes the holes into account. There are pros and cons to using each method, but the NSIDC uses extent.

The chart above shows the Arctic Sea Ice extent from the past several years, in comparison with the 1979-2006 averages. Obviously, we are still well below the 1979-2006 averages, so it is not time to “cancel” global warming. However, we have had a very significant recovery from this time last year — it is almost two million square kilometers above last year’s level! This is great news. Although we are really only near the 2009 level and not necessarily that deviant from the past several years, the increase is quite significant and a bit unprecedented, since year-to-year increases of this magnitude are rare.

 

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Doug Simonian

What Explains the Convective Cumulus Clouds we had Yesterday?

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Convective cumulus clouds were observed throughout the area on Monday, and many areas saw snow pellets falling despite temperatures in the upper 40's to near 50. Some very interesting atmospheric processes were at work to cause this, which we detail below.

Convective cumulus clouds were observed throughout the area on Monday, and many areas saw snow pellets falling despite temperatures in the upper 40’s to near 50. Some very interesting atmospheric processes were at work to cause this, which we detail below.

Skies finally cleared somewhat on Monday behind our departing storm system. As some of you may have noticed, we observed lots of cumulus clouds today, almost as if it were summer, despite relatively chilly temperatures. Additionally, they actually had pretty good, organized vertical structure (although not towering), and some were quite dark. Isn’t this usually a summer time convection phenomenon? What explains this?

This is where it is very important to look at what we call lapse rates. Lapse rates are the difference in temperature between two given heights in the atmosphere. Thus, a steep lapse rates means that there is a great difference in temperature between the bottom of the given layer and the top of the given layer. Mathematically, they are actually the negative of the difference in temperature divided by the change in height, since temperatures generally decrease with height. Thus, when temperatures rapidly decrease as you increase in height, you have a strong, positive lapse rate. When lapse rates are strongly positive, that means the atmosphere is very unstable.

Now, let’s apply this to the atmosphere. There is the cliche that warm air rises and cold air sinks, and this is because cold air is more dense than warm air. Thus, when an air parcel (a sample of air) is heated at the surface, it will have the tendency to rise. And if that heated parcel is rising into air that is rapidly getting colder with height, that means the parcel will have a tendency to keep rising, since it is much warmer than the air around it and above it during its rise. Thus, steep lapse rates means that you have rapidly rising air.

Usually, when we evaluate the stability of the atmosphere, we like to start with the ground layer, since the ground is what traps sunlight and heats most efficiently. If we know the temperature at the ground is much warmer than the temperatures in the mid levels of the atmosphere, then we have an unstable atmosphere and rapidly rising air. Let’s take a look at the atmospheric conditions and see if we have these phenomena taking place.

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