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Konstantinos

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Everything posted by Konstantinos

  1. Hello flyer. I understood about magnetic north and true north. Thank you. If I have a compass, then I can see where is the magnetic north. But how can I see where is the true north? Soon, I will take a weather handheld multimeter which can show me the true heading and the magnetic heading. How can it show me the true heading? It does not have connection with gps - satellite or mobile internet or something similar. It only has a digital compass. I am wondering because the angle between true north and magnetic north changes and it depends on my position. For example in the center of Canada, or in the center of USA (maybe in Texas), the direction of magnetic north is the same than the direction of true north, but in Greece it is different. If you live in the straight line which begins from magnetic north and ends in true north, then you will see that the two norths have 180 degrees difference: http://upload.wikimedia.org/wikipedia/commons/0/0a/Magnetic_North_Pole_Positions.svg Also, I understand about the degrees and the names. To summarize, we have: 0 - 11.25 N 11.25 - 33.75 NNE 33.75 - 56.25 NE 56.25 - 78.75 ENE 78.75 - 101.25 E 101.25 - 123.75 ESE 123.75 - 146.25 SE 146.25 - 168.75 SSE 168.75 - 191.25 S 191.25 - 213.75 SSW 213.75 - 236.25 SW 236.25 - 258.75 WSW 258.75 - 281.25 W 281.25 - 303.75 WNW 303.75 - 326.25 NW 326.25 - 348.75 NNW 348.75 - 360 N I hope I have understood it and I am right, dear flyer.
  2. I am trying to understand better, what is water vapor - moisture and what exactly is the saturation. When we have a sponge under the water, for example under the sea level, "it is saturated"? Water vapor is the gas version of water? If we heat the ice (solid), we take water (liquid), and if we heat water (liquid), we take water vapor (gas)? I have understood well? Why the air cannot take in more water vapor? What is the reason and what is the limit? If we have two similar closed boxes, what is the difference if the one has 100% saturated air and the other has 100% water from sea?
  3. Ok, thank you very much. You explained clearly and I understood clearly. The last two questions: So, I suppose, 0 degrees is the true north, not the magnetic north. Right? When the direction is 30 degrees, we choose between NE(45 degrees) and ENE(22.5 degrees), right? So, we choose ENE because 30 - 22.5 < 45 - 30?
  4. What exactly is the density altitude? I have not understood it. We say for altitude or elevation: I am 2.000 m ABOVE MEAN SEA LEVEL. What we say for denisty altitude? I am 2.000 m ABOVE WHAT? If I am in a mountain peak which is 2.000 m above sea level, then can my density altitude be 1.500 m? 2.000 m? 2.500 m? Is there a formula - function which gives me the density altitude? It depends on altitude, temperature and humidity? What humidity? Absolute or relative? Thank you.
  5. Here: http://www.crh.noaa....cu/humidity.php I read this: The dewpoint temperature, which provides a measure of the actual amount of water vapor in the air, is the temperature to which the air must be cooled in order for that air to be saturated. I cannot understand what is the meaning of the phrase "Air is saturated". Can you explain to me? Also, it says: Meteorologists routinely consider the "dewpoint" temperature (instead of, but analogous to absolute humidity) to evaluate moisture, especially in the spring and summer. What is the relation between dewpoint and absolute humidity? The unit of absolute humidity is grams of water vapor per cubic meter volume of air, and the unit of dewpoint temperature is the degrees C or degrees F? I am right? The unit of dewpoint? How dew point influences in our body's feelings? And finally tell me about wet bulb temperature and dry bulb temperature. Thank you.
  6. First question, when we say North Wind, it is reported with reference to true north or to magnetic north? I have not understood the symbols N, NE, WNW etc. Can you explain to me them? For example N, is 0 or 360 degrees. Right? S is 180 degrees? NNE? NE? WNW? Explain to me please and thank you.
  7. I reminds me a week in Athens, in 2007, when we had 47 degrees during noon - midday and 42 degrees during night... I had cold shower every 30 minutes...
  8. I saw that the situation in India is very dangerous, with very low temperatures... 20 people died... What do you know?
  9. New Zealand? Auckland? What is the history of this region about tropical cyclones?
  10. I have not understood yet. From this mathematical formula: http://en.wikipedia....ssure_variation I can see that the altitude depends only on the pressure. Nothing else. So, if I know the pressure of my position I can find my altitude? Doesn't it depends on the pressure of my nearest sea? What is the mistake on this mathematical formula? Or the "sea level standard atmospheric pressure" p0 is not constant?
  11. And what about if I am in a stable altitude, without moving, but the pressure is changing? The changes are not enough for changing my altitude? For example now in my region I think we have 990 hPA but 12 hours ago we had 995 hPa. So?
  12. How an instrument calculates the altitude? Can you explain? If it knows the pressure, then how altitude is calculated? And the altitude depends on pressure? Only on pressure?
  13. Yes you are right... Thank you. But I hope the things WILL NOT change... I hope so... Anyway, I will follow you every day...
  14. Sorry, I was talking about next next week... 7 - 8 - 9 - ... - 12 December.
  15. What is your opinion about the cold which is coming in Central - Eastern Europe and Greece the next week?
  16. What is your opinion about the cold which is coming in Central - Eastern Europe and Greece the next week?
  17. Supposing the average rain type, size and volume of water per drop? Do we know how many m^3 is the volume of an average drop?
  18. If I know the precipitation of rain in a region will be A mm for 6 hours, then how can I calculate the average drops of rain per second for a square meter? Thank you.
  19. Thank you very much. A good suggestion... Only humidity is not offered by this... But ok, I do not worry...
  20. Hi friends. I am looking for a weather station to take with me, during my hiking in mountains. I want this station shows: 1) Time 2) Temperature 3) Humidity 4) Realfeel temperature 5) Pressure 6) Altitude (Basic) 7) My hiking speed (Optional) 8 ) The lenght of my route - trip - way (Optional) 9) The degrees of angle in uphills and downhills (Optional) 10) The available oxygen %? (Optional) Suggestions? Thank you.
  21. Can I install a smart weather station in my house, which will forecast the weather in it for the coming hours, with more accurately than the sites do? Will it be useful? Thank you.
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