Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics
description
Transcript of Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics
![Page 1: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/1.jpg)
![Page 2: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/2.jpg)
Earth – Maps and Navigation
size/shape/rotation of Earth is fundamental to ocean dynamics
- interesting to know history of Earth’s geometry
- need to know how to describe location and size of features
- bit of navigational history (can use oceans/celestial)
Geography 104 - “Physical Geography of the World’s Oceans”
![Page 3: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/3.jpg)
Greek mathematician, poet, athlete, geographer and astronomer
Eratosthenes of Cyrene (c.275-192):
http://www.livius.org/aj-al/alexander/alexander_t33.html
Interesting to know
![Page 4: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/4.jpg)
http://epod.usra.edu/archive/epodviewer.php3?oid=61280
800 km
Alexandria & Syene
(Aswan)
![Page 5: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/5.jpg)
Eratosthenes’ estimate of earth’s diameter
http://www.nos.noaa.gov/education/kits/geodesy/media/supp_geo02a.html
360º x 800 km 7.2º
C =
C = earth’s circumference = 40,000 km
= 7.2°
![Page 6: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/6.jpg)
Eratosthenes’ estimate of earth’s diameter
http://www.nos.noaa.gov/education/kits/geodesy/media/supp_geo02a.html
7.2 º360º =
800 km C
C = earth’s circumference = 40,000 km (stadia)
= 7.2°
Modern estimate of Earth’s radius,re = 6371 kmC=2re = 40,030 km
![Page 7: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/7.jpg)
Eratosthenes
![Page 8: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/8.jpg)
polar radius = 6357 kmequatorial radius = 6378 = 0.9967
radius of sphere with Earth’s volume is 6371 km
non-spherical shape important for satellite orbits
![Page 9: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/9.jpg)
Latitude and Longitude – Mollweide projection
latitude line (equator only great circle latitude) longitude line (great circle)
zonal
meridional
![Page 10: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/10.jpg)
Latitude and Longitude – Mollweide projection
latitude line longitude line
360 deg/1 day = 15 deg/hr
![Page 11: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/11.jpg)
special latitude & longitude lines
axial tilt of the Earth with respect to the sun is 23° 26′ 21.41″
![Page 12: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/12.jpg)
circle – subtends angle of 360°1° = 60’ (minutes)1’ = 60” (seconds)
nautical mile = distance of 1° latitude
distance / degree latitude is constantnot true for longitude
re = 6371 km
circumference = 2πre = 40,030 km
r e =
637
1 kmc lat
1° / 360° = Clat / 40,030 km
Clat = 40,030 km / 360° = 111 km/°lat = 60 nm/°lat
= 69 mi/°lat
distance per degree of latitude
![Page 13: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/13.jpg)
distance / degree not constant for longitude
re = 6371 km
Φ = latitude
circumference = 2πrecosΦ = 40,030km cosΦ
r e =
637
1 km
1° / 360° = Clon / 40,030km cosΦ
Clon = 111 km cosΦ km/°lon
distance per degree of longitude
ϕ
re cos Φ
![Page 14: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/14.jpg)
A
B
d
x
y
- can use Pythagorean Theorem to obtain accurate distance estimate between two points- accurate for distances around 100 km or less
![Page 15: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/15.jpg)
34° 20’
34° 10’
120° 10’ 120°
A
B
A = 34° 20’ = 34° + 20/60° = 34.333°
B = 34° 10’ = 34° + 10/60° = 34.167°
A - B = 0.166°
A =
B = y
![Page 16: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/16.jpg)
34° 20’
34° 10’
120° 10’ 120°
A
B
y = (111 km/°lat)(0.166 °lat) = 18.3 km
A =
B = y
![Page 17: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/17.jpg)
120° 10’ 120°
A
B
=AB =
x
x = (111*cos(34+15/60) km/°lon)(0.167 °lon) = 15.2 km
34° 15’
![Page 18: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/18.jpg)
A
B
d
x
y
d = (x2+y2)1/2 = (18.42+15.22)1/2 = 23.9 km
![Page 19: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/19.jpg)
early Pacific navigation
![Page 20: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/20.jpg)
early Pacific navigation
![Page 21: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/21.jpg)
early Pacific navigation
![Page 22: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/22.jpg)
early Atlantic navigation
![Page 23: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/23.jpg)
Latitude determination
![Page 24: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/24.jpg)
antique navigational instruments
![Page 25: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/25.jpg)
horizon
North Star
latitude
using a cross staff
![Page 26: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/26.jpg)
sextant
![Page 27: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/27.jpg)
using a sextant
![Page 28: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/28.jpg)
Gemma Frisius 1508 – 1555
mathematician, cartographer, instrument maker, first to describe how an accurate clock could be used to determine longitude
![Page 29: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/29.jpg)
Longitude determination
rotation rate = 360 deg in 24 hr = 15 deg per hr
15°
![Page 30: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/30.jpg)
Set clock on boat before departing from Greenwich.
Longitude determination
![Page 31: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/31.jpg)
What is longitude if clock on boat reads 16:18 at local noon?
Longitude determination
![Page 32: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/32.jpg)
Local noon is behind clock => boat is west of Greenwich
Longitude determination
![Page 33: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/33.jpg)
time difference = 4+ hr = 4.3 hr longitude difference = 4.3 hr x 15°/hr = 64.5° W
1860
Longitude determination
![Page 34: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/34.jpg)
![Page 35: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/35.jpg)
John Harrison (1693-1776)
Clocks for measuring longitude
![Page 36: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/36.jpg)
global sea surface temperature from satellite observations
![Page 37: Earth – Maps and Navigation size/shape/rotation of Earth is fundamental to ocean dynamics](https://reader036.fdocuments.us/reader036/viewer/2022062309/56814e3b550346895dbba3ae/html5/thumbnails/37.jpg)
Readings for next time (Seafloor):-Read Chapter 4 “Seafloor Features”; article “Emergence of Complex Societies After Sea Level Stabilized”; article “Risk of Rising Sea Level to Population and Land Area”