INFRARED IMAGE COLOR SCALES
Satellite images make it easier to stay out of harm’s way as you sail the seven seas.
While enhanced infrared images are extremely helpful, interpreting them can be confusing.
The color scale on enhanced images varies with the source of the image.
The color scale is different with EUMETSAT images and GOES images. Some scales use Centigrade temperatures and others use Kelvin Temperatures.
In the Kelvin Scale, absolute zero is -273 degrees Kelvin, and water freezes at +273 K.
Any temperature signature less than +273 degrees means water droplets get frozen into ice. High clouds contain lots of ice crystals.
When you go to Windy.com and look at the enhanced infrared images, you can read the temperature of the cloud tops by putting the cursor on the cloud. You literally explore the temperature of the cloud tops with your cursor. The Kelvin Scale in this graphic (240K to 200K) are all temperatures below freezing. The smaller the number, the colder the temperature.
Being able to directly read the Kelvin temperatures off the top of high clouds gives you an idea of how strong the convection is in a particular thunderstorm based on the height/temperature of the clouds.
Color scales can display cloud temperature in incremental steps, or it can take the form of a continuous color scale.
A continuous color scale is more precise because the cloud temperatures are not limited to incremental jumps found in a stepped scale.
The Kelvin Scale found on Windy is a continuous scale making it easier to precisely define the different temperatures in the clouds in a convection event.
The step scale creates a band of cloud temperatures for each colored step.
GOES weather images uses a step scale.
Each shade of gray or distinct color represents a range of 5 degrees Celsius (9 degrees Fahrenheit).
Colors are assigned to the following temperatures:
* Blue: -40 to -45 degrees C (or -40 to -49 degrees F);
* Cyan: -45 to -50 degrees C (or -49 to -58 degrees F);
* Green: -50 to -55 degrees C (or -58 to -67 degrees F);
* Yellow: -55 to -60 degrees C (or -67 to -76 degrees F);
* Red: -60 to -65 degrees C (or -76 to -85 degrees F);
* Violet: -65 to -70 degrees C (or -85 to -94 degrees F).
* Temperatures colder than -70 degrees C are assigned a light shade of gray indicating extremely cold high altitude cloud tops.
The disadvantage of a stepped color scale is that it is less precise. Some fine details of cloud top structure my not be visible. They are hidden in the steps, whereas they are visible on a continuous or Kelvin scale.
Infrared satellite images record invisible infrared radiation emitted by ocean, land, and the tops of clouds. Warmer objects emit more radiation and colder objects emit less.
Infrared images are really negatives, and white areas are colder (emit less infrared light), and areas that are dark are warmer. The negatives are displayed so that the images look similar to visible images.
Enhanced infrared images use colors to differentiate the temperature of land, sea and clouds. High clouds are very cold and have a different color than lower clouds that are warmer.
Real Ocean Cruisers mainly use visible satellite imagery and enhanced infrared images together to get a better picture of the weather.
Visible satellite images reveal the presence of clouds and are good at visualizing low level clouds that may not show up on infrared images. They show thin clouds as well. Unfortunately, the visible images can only be taken in daytime, and they are useless at night.
Plain infrared images are actually negatives of the infrared image which makes the infrared image more closely resemble visible images. If positive images were used, high clouds would be black and land and sea would be nearly white.
The combination of visible light images, and infrared images helps you understand what’s happening to the weather in your small patch of paradise.
Once you understand the color scale of infrared images, you become an expert at reading the sky.
That’s all I have to say about that.
Captain Dave
Awesome music video that captures the essence of what it's like to sail offshore in a catamaran around the world when conditions are less than perfect. David Abbott from Too Many Drummers sings the vocals, and he also edited the footage from our Red Sea adventures. This is the theme song from the Red Sea Chronicles.
Sailing up the Red Sea is not for the faint of heart. From the Bab al Mandeb to the Suez Canal, adventures and adversity are in abundance. If you take things too seriously, you just might get the Red Sea Blues.
If you like drum beats, and you like adventure, then have a listen to the Red Sea Chronicles Trailer.
Flying fish assault Exit Only in the middle of the night as we sail through the Arabian Gulf from the Maldives to Oman. And so begins our Red Sea adventures.
Sailing through Pirate Alley between Yemen and Somalia involves calculated risk. It may not be Russian Roulette, but it is a bit of a worry. Follow Team Maxing Out as they navigate through Pirate Alley.
Stopping in Yemen was just what the doctor ordered. We refueled, repaired our alternator, and we made friends with our gracious Yemeni hosts. We also went to Baskins Robbins as a reward for surviving Pirate Alley.
After you survive Pirate Alley, you must sail through the Gate of Sorrows (Bab Al Mandab) at the southern entrance to the Red Sea. The Gate of Sorrows lived up to its name with fifty knots of wind and a sandstorm that pummeled Exit Only for two days. Life is good.
Captain Dave and his family spent eleven years sailing around the world on their Privilege 39 catamaran, Exit Only. During the trip, the crew shot 200 hours of video with professional cameras to show people what it's like to sail on a small boat around the world.
The Red Sea Chronicles is a one hour and twenty-two minute feature film showing their adventures as Exit Only sails through Pirate Alley in the Gulf of Aden and up the Red Sea. The professional footage documents their experiences in Oman, Yemen, Eritrea, Sudan, Egypt, and the Suez Canal. It chronicles the rigors of traveling in a remote section of the world rarely visited by cruisers. Exit Only dodges Yemeni pirates, fights a gale and sand storms in the Bab al Mandeb at the southern entrance to the Red Sea. The crew explores deserted islands on the western shores of the Red Sea, and learns to check the cruising guides for land mines before venturing ashore.
The Red Sea Chronicles also has outstanding Special Features including an Instructional Video on Storm Management that tells sailors how to deal with storms at sea.
And don't forget the two Music Videos: "The Red Sea Blues", and "Captain - Save Our Souls".
The Red Sea Chronicles is a first class adventure that stokes the sailing dreams of both experienced and wannabe sailors alike.
Join Team Maxingout as they sail through Pirate Alley and up the Red Sea
See what it's like to cruise on a catamaran before you spend a bazillion dollars purchasing one
After watching the Red Sea Chronicles you will be able to see yourself sailing on the ocean of your dreams
Although I like the feel of a paper book in my hand, I love trees even more. When people purchase an eBook, they actually save trees and save money as well. Ebooks are less expensive and have no negative impact on the environment. All of Dr. Dave's books are available at Save A Tree Bookstore. Visit the bookstore today and start putting good things into your mind. It's easy to fill your mind with positive things using eBooks. No matter where you are or what you are doing, you can pull out your smart phone or tablet and start reading. You can even use electronic highlighters and make annotations in your eBooks just like paper books.
