יום שלישי, 2 בינואר 2018

Climate Change 2.0 My Version of the True
By Tsahi Frankovits, January 2, 2018

POTUS D.J.T has three alternative ideas about Global Warming:

The first one is there's no such thing as global warming
The second even if there's global warming, it has nothing to do with human activities.
The third even if there's global warming and humans are responsible, we (the US) shouldnt be the one to pay the price.

I don't intend to judge the U.S president's internal logic, nor I'm able to proof any linkage between weather and human activities that's not my goal. I'm here to offer a somewhat different view on the last 50 years weather phenomena and show that, well something significant is happening in our lifetime and it's a bit disturbing.
In this first article I'll give you a single snapshot in to my findings. later I'll dive deeper into the phenomena and the new picture of the seasons as I see it through my data and analytical models. The last article in this short series I will describe some of the ideas I've been using to generate these results.

A word about the data I'm using: it's a data set on meteorological measurements in a single weather station here in central Israel. I'm using bi-hourly measures (12 data points a day) for a variety of weather features such as temperatures, wind speed, moisture etc. And a daily measure of precipitation. The data was taken from Israel Meteorological Service web site.    

 Let's go straight to business

When people are talking about global warming they talk about the rise of average temperatures during the last 50 years, the increase of extreme weather phenomenon, growing sea levels etc. But it's always start with average temp.

The focus on temperatures as the main measure or manifestation of climate changes has drown my attention for two reasons: First how do you measure average temp. on a global scale.  Second its a slow process that people can not refer to. You can't feel global warming.

On the other hand, if you ask people about the weather now they'll say that it's a wintry day, a nice and pleasant spring day or a very hot summer day. But wintry day refers to many different aspects of weather it may feel wintry because it's rainy, or because it's cold outside and/or windy etc.  We perceive weather as a more complex experience as just temperature. This notion has led me to think that what I should look for is a way to characterize the days over the year based on their weather-related characteristics. That means a day is a wintry day not because it's winter now (a fixed time window during the year or "the season") but because it has the features of a wintry day.

So now that I know what the days are really like, I can look back 50 years in to the past and reveal a new and more interesting view of our weather. Here is the first glimpse of it:  

In the following chart you see how days were distributes over the years based on their actual seasonal characteristics. And the somewhat disturbing true is obvious to the eye.

We're in the center of Israel and what we see is that the percentage of summer days in every year moved up from around 35% (until the early 90') to more then 40% of the year (i.e. from 127 days to 153 days a year) and wintry days, which were at their pick in the mid 80' around 30% of the year (109 days) are consistently dropping since then and are below 20% (~70 days) of the year during the last 10 years or so.

People who live in central Israel say that "we are not buying coats to our kids any more". It's not because summer are warmer but because winters are, well, not as wintery as we remember from our days as young kinds in the country.


In the next article we'll talk about measuring the actual length of seasons and see how climate changed our seasons, moving to 3 or even 2.5 seasons' world (at least to us in this small corner of the world).

Tsahi

אין תגובות:

הוסף רשומת תגובה