Etudes et évaluation de processus océaniques par des hiérarchies ...

More documents

Recommendations

Info

• • 188 14 CHAPTER 3. PHYSICAL PROPERTIES OF SEA WATER tel-00545911, version 1 - 13 Dec 2010 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 26 44 45 33 34 35 36 27 28 46 Figure 3.3: θ-S-diagram; potential density 0 dbar lines and σ 0 -values are shown in blue; potential density 4000 dbar lines and σ 4000 -values are shown in red. The figure ilustrates the phenomenon of thermobaricity. The hotter and saltier water mass is heavier at the surface and lighter at 4000m depth than the other water mass. This happens because hot water is less compressible than colder water.
189 3.7. CONSERVATIVE PROPERTIES 15 3.7 Conservative Properties The dynamics of a tracer S transported by an incompressible fluid of velocity field u, diffused with the diffusion κ and subject to sources and sinks Q is govenred by the advection diffusion equation: ∂ t S + u · ∇S − ∇ · (κ∇S) = Q. (3.6) tel-00545911, version 1 - 13 Dec 2010 A scalar is said to be conservative if Q = 0. Besides their important influence on the density there is another reason why salinity and potential temperature play such an important role in oceanography they are conservative. Away from the boundaries these properties can only be changed by mixing with water masses of different characteristics. Pleae note, that temperature is not conservative as it changes when a water parcel is transported up or down in the ocean, when pressure changes. This is equivalent to say, that there are no sources or sinks of salinity and potential temperature in the ocean interior. Other scalars like dissolved oxygene nutrients and biological concentrations are not conservative as they have sinks and sources. 3.8 Water Masses in the Ocean Water in the ocean mixes due to molecular diffusion and turbulent stirring (see section 10.2). In large parts of the ocean, away from the boundaries, the mixing is small. Water parcels thus conserve their conservative characteristics, salinity and potential temperature, when transported over long distances and a mean large scale transport velocity of water masses and the velocity field in the ocean can be determined by measuring potential temperature and salinity. Further more, water mass characterisitics change only slowly in the deep ocean and show only small variations over the years. These changes can be used as important indicators of climate (long-time-large-space) variability. 3.9 Sea Ice and Ice Bergs Fresh water freeszes at 0 o C and sea water with a salinity of 35psu freezes at −1.8 o C, at atmospheric pressure. Fresh water has its maximal density at 4 o C, when lakes cool below this temperature the cold water stays at the surface and freezing happens quickly near the surface while 4 o C warm water is found in the deep lake. The ice formation of lakes mostly depends on the atmospheric temperature and the wind speed. For water with a salinity over 24.7psu the maximum density is at the freezing temperature. When the ocean is cooled the cold surface water descents and is replaced by warmer water from depth until the freezing temperature is reached. Sea water can only freeze when the cooling from the atmosphere is stronger than the convective warming from the deep ocean. So, for the formation of sea ice, besides atmospheric temperature and the wind speed, the water depth and the stratification of the ocean in temperature and salinity are important parameters. No such convective warming is present for fresh water lakes once the temperature is below 4 o C, and indeed you can go ice-skating on lakes in northern Europe while the nearby sea is completely ice free. The vertical convection process is studied in section 10.3. Ice cover are crucial to the ocean dynamics as it: (i) has a strong influence on the reflection of the incoming radiation, especially when they are covered by fresh snow (see section 4.1.1),
Page 1 and 2:
Mémoire de Recherche présenté pa
Page 3 and 4:
tel-00545911, version 1 - 13 Dec 20
Page 5 and 6:
Table des matières I Etudes de pro
Page 7 and 8:
Première partie tel-00545911, vers
Page 9 and 10:
Chapitre 1 Avant-propos tel-0054591
Page 11 and 12:
Chapitre 2 Comprendre la dynamique
Page 13 and 14:
2.3. HIÉRARCHIE DE TYPES DE MODÈL
Page 15 and 16:
2.3. HIÉRARCHIE DE TYPES DE MODÈL
Page 17 and 18:
2.5. MA RECHERCHE DANS LE CONTEXTE
Page 19 and 20:
Page 21 and 22:
Chapitre 3 Dynamique océanique et
Page 23 and 24:
3.1. LA CIRCULATION OCÉANIQUE À G
Page 25 and 26:
3.1. LA CIRCULATION OCÉANIQUE À G
Page 27 and 28:
3.2. PROCESSUS SUBMÉSO ECHELLES ET
Page 29 and 30:
3.4. RETOUR À LA GRANDE ECHELLE PA
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Bibliographie tel-00545911, version
Page 37 and 38:
Deuxième partie tel-00545911, vers
Page 39 and 40:
33 Curriculum Vitae du Dr. Achim WI
Page 41 and 42:
35 tel-00545911, version 1 - 13 Dec
Page 43 and 44:
Colloque bilan LEFE, Plouzané, Mai
Page 45 and 46:
Troisième partie tel-00545911, ver
Page 47 and 48:
Chapitre 4 Etudes de Processus Océ
Page 49 and 50:
4.1. VARIABILITY OF THE GREAT WHIRL
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
4.2. THE PARAMETRIZATION OF BAROCLI
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
4.3. A NON-HYDROSTATIC FLAT-BOTTOM
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
4.4. TILTED CONVECTIVE PLUMES IN NU
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
4.5. MEAN CIRCULATION AND STRUCTURE
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
4.6. ESTIMATION OF FRICTION PARAMET
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
4.7. ON THE BASIC STRUCTURE OF OCEA
Page 139 and 140:
Page 141 and 142:
Page 143 and 144: 4.7. ON THE BASIC STRUCTURE OF OCEA
Page 151 and 152: 4.8. ESTIMATION OF FRICTION LAWS AN
Page 167 and 168: 4.9. ON THE NUMERICAL RESOLUTION OF
Page 179 and 180: Quatrième partie tel-00545911, ver
Page 181 and 182: 175 tel-00545911, version 1 - 13 De
Page 183 and 184: 177 Contents 1 Preface 5 tel-005459
Page 185 and 186: 179 Chapter 1 Preface tel-00545911,
Page 187 and 188: 181 Chapter 2 Observing the Ocean t
Page 189 and 190: 183 Chapter 3 Physical properties o
Page 191 and 192: 185 3.3. θ-S DIAGRAMS 11 3.3 θ-S
Page 193: 187 3.6. HEAT CAPACITY 13 tel-00545
Page 197 and 198: 191 Chapter 4 Surface fluxes, the f
Page 199 and 200: 193 4.2. FRESH WATER FLUX 19 water.
Page 201 and 202: 195 Chapter 5 Dynamics of the Ocean
Page 203 and 204: 197 5.2. THE LINEARIZED ONE DIMENSI
Page 205 and 206: 199 5.4. TWO DIMENSIONAL STATIONARY
Page 207 and 208: 201 5.6. THE CORIOLIS FORCE 27 Whic
Page 209 and 210: 203 5.8. GEOSTROPHIC EQUILIBRIUM 29
Page 211 and 212: 205 5.10. LINEAR POTENTIAL VORTICIT
Page 213 and 214: 207 5.13. A FEW WORDS ABOUT WAVES 3
Page 215 and 216: 209 Chapter 6 Gyre Circulation tel-
Page 217 and 218: 211 6.1. SVERDRUP DYNAMICS IN THE S
Page 219 and 220: 213 6.2. THE EKMAN LAYER 39 In the
Page 221 and 222: 215 6.3. SVERDRUP DYNAMICS IN THE S
Page 223 and 224: 217 Chapter 7 Multi-Layer Ocean dyn
Page 225 and 226: 219 7.3. GEOSTROPHY IN A MULTI-LAYE
Page 227 and 228: 221 7.5. EDDIES, BAROCLINIC INSTABI
Page 229 and 230: 223 Chapter 8 Equatorial Dynamics t
Page 231 and 232: 225 Chapter 9 Abyssal and Overturni
Page 233 and 234: 227 9.2. MULTIPLE EQUILIBRIA OF THE
Page 235 and 236: 229 9.3. WHAT DRIVES THE THERMOHALI
Page 237 and 238: 231 Chapter 10 Penetration of Surfa
Page 239 and 240: 233 10.2. TURBULENT TRANSPORT 59 If
Page 241 and 242: 235 10.5. ENTRAINMENT 61 instabilit
Page 243 and 244: 237 Chapter 11 Solution of Exercise
Page 245 and 246:
239 65 Exercise 32: The moment of i
Page 247 and 248:
241 INDEX 67 Transport stream-funct
Page 249 and 250:
Annexe A Attestation de reussite au
Page 251 and 252:
Annexe B Rapports du jury et des ra
Page 253 and 254:
tel-00545911, version 1 - 13 Dec 20
Page 255 and 256:
tel-00545911, version 1 - 13 Dec 20
Page 257 and 258:
251 utilisés avec pertinence. Sur
Page 259 and 260:
253
Page 261 and 262:
tel-00545911, version 1 - 13 Dec 20
show all

Etudes et évaluation de processus océaniques par des hiérarchies ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?