chapter - Atmospheric and Oceanic Science

More documents

Recommendations

Info

11.1. Introduction Global climate models A large number of climate change experiments using Global Climate Models (GCMs) have been completed in recent years, both equilibrium and transient experiments, and both experiments forced with changes in greenhouse gas concentrations alone and those forced with greenhouse gas and sulphate aerosol changes. A number of parallel experiments have also been completed using high resolution Regional Climate Models. Results from a considerable number of these experiments have been used in climate change impacts and adaptation assessments. It is not always easy, however, to know which experiment has been used in an impacts study, nor how the particular modelling results fit into the larger population of GCMs climate change experiments. Comprehensive climate models are based on physical laws represented by mathematical equations that are solved using a three-dimensional grid over the globe. For climate simulation, the major components of the climate system must be represented in sub-models (atmosphere, ocean, land, surface, cryosphere and biosphere), along with the process that go on within and between them. Global climate models in which the atmosphere and ocean components have been coupled together are also known as Atmosphere-Ocean General Circulation models (AOGCMs). Most results to be presented in this report are derived this kind of models. Climate models have developed over the past few decades as computing power has increased. During that time, models of the main components, atmosphere, land, ocean and sea ice have been developed separately and then gradually integrated. This coupling of the various components is a difficult process. Most recently, sulphur cycle components have been incorporated to represent the emissions of sulphur and how they are oxidized to form aerosol particles. Currently in progress, in a few models, is the coupling of the land carbon cycle and the ocean carbon cycle (IPCC 2001). The atmospheric chemistry component is currently modelled outside the main climate model. The ultimate aim is to model as much as possible of the whole of the Earth's climate system so that all the components can interact and, thus, the predictions of climate change will continuously take into account the effect of feedbacks among components. Figure 11.1, obtained from the Intergovernmental Panel on Climate Change report from 2001 (IPCC 2001), shows the past, present and possible future evolution of climate models. In summary, from the description above, one can see that the GCMs can be very complex, however, can we grasp how do they work? In the next section, some basic ideas about these models will be addressed. 141
Global climate models Mid-1970’s Mid-1980’s Early 1990’s Late 1990’s Present day Early 2000’s? Atmosphere Atmosphere Land surface Ocean & sea-ice model Atmosphere Land surface Ocean & sea-ice Sulphur cycle mode Land carbon cycle model Ocean carbon cycle model Atmosphere chemistry Atmosphere Land surface Ocean & sea-ice Sulphate aerosol Non-sulphate aerosols Carbon cycle model Dynamic vegetation Atmosphere chemistry 11. 2. Atmospheric General Circulation Models (AGCMs) Zero-, one- and two-dimensional climate models present a qualitative picture of how the atmospheric climate system works. However, these models either neglect various processes that are known to be important in the atmosphere, or they use simple mathematical representations for these atmospheric process. The representation of these processes is called parameterization. In order to accurately account for the general motions of the atmosphere requires the solution of a complete set of equations. The solution of these equations on the sphere, given realistic boundary conditions, defines the AGCM (Trenberth 1993). An AGCM to be implemented requires: a numerical solution technique, algorithms for the various physical parameterizations, and boundary data sets for predetermined vertical and horizontal resolutions. The solution of the system of equations (called primitive) and parameterizations proceeds is outlined in figure 11.2. Assuming initial data are available for the prognostic variables, the model calculates initial fluxes for use in the planetary boundary layer (PBL) and surface components of the model. These, along with the thermodynamic and moisture profiles at each gridpoint, are used to test whether the atmospheric column is stable or unstable. If unstable, a convection parameterization is used to determine the convective heating and moistening terms. Otherwise, if saturated, the stable condensa- 142 Atmosphere Land surface Ocean & sea-ice Sulphate aerosol Non-ulphate aerosol Carbon cycle Dynamic vegetation Atmosphere chemistry Atmosphere Land surface Ocean & sea-ice Sulphate aerosol Non-ulphate aerosol Carbon cycle Dynamic vegetation Atmosphere chemistry Fig. 11.1. Development of climate models over the last 25 years showing how the different components were first developed separately and later coupled into comprehensive climate models. [Source: IPCC 2001]
Page 1 and 2:
CLIMATE CHANGE IN THE LA PLATA BASI
Page 3 and 4:
INDEX FOREWORD . . . . . . . . . .
Page 5 and 6:
7.3. Methodology . . . . . . . . .
Page 7 and 8:
13.3. Regional validation of GCM fo
Page 9 and 10:
1.1. Dropping the hypothesis of sta
Page 11 and 12:
Introduction as they pour water ove
Page 13 and 14:
A better understanding of the obser
Page 15 and 16:
References Introduction Barros, V.
Page 17 and 18:
ABSTRACT The hydrologic cycle of th
Page 19 and 20:
La Plata basin climatology Within t
Page 21 and 22:
in this last description, although
Page 23 and 24:
warm season (October-April), in the
Page 25 and 26:
La Plata basin climatology b. Upper
Page 27 and 28:
La Plata basin climatology 2.3.3. R
Page 29 and 30:
La Plata basin climatology Fig. 2.8
Page 31 and 32:
2.3.7. West and South borders La Pl
Page 33 and 34:
References La Plata basin climatolo
Page 35 and 36:
La Plata basin climatology Robertso
Page 37 and 38:
3.1. Introduction Interannual low f
Page 39 and 40:
Interannual low frequency variabili
Page 41 and 42:
1989). This signal varies along eac
Page 43 and 44:
Interannual low frequency variabili
Page 45 and 46:
The main physiographic and hydrolog
Page 47 and 48:
SUB-BASIN COUNTRY Argentina Bolivia
Page 49 and 50:
the most important stretches of the
Page 51 and 52:
Physiography and Hydrology The Para
Page 53 and 54:
Physiography and Hydrology The Pant
Page 55 and 56:
Physiography and Hydrology forcings
Page 57 and 58:
Physiography and Hydrology It is no
Page 59 and 60:
Physiography and Hydrology tion of
Page 61 and 62:
Physiography and Hydrology INTERNAV
Page 63 and 64:
5.1. Introduction Precipitation and
Page 65 and 66:
From 1956 to 1991, in most of the A
Page 67 and 68:
-15 -20 -25 -30 -35 -40 -15 -20 -25
Page 69 and 70:
Regional precipitation trends 5.3.2
Page 71 and 72:
Regional precipitation trends and L
Page 73 and 74:
trast, other regions suffer floodin
Page 75 and 76:
ABSTRACT The main hydrological tren
Page 77 and 78:
Following are the observed changes:
Page 79 and 80:
In the case of the Paraná River th
Page 81 and 82:
Hydrological trends In order to com
Page 83 and 84:
Hydrological trends In table 6.1 it
Page 85 and 86:
Hydrological trends On the other ha
Page 87 and 88:
the central area of the high basin
Page 89 and 90:
7.1. Introduction Several authors,
Page 91 and 92: Real evaporation trends a) PET > Pi
Page 93 and 94: a) b) c) Mean Temperature Real evap
Page 97 and 98: The positive trends of the mean tem
Page 99 and 100: d) e) f) Mean Temperature Real evap
Page 103 and 104: 7.5. Discussion and final comments
Page 105 and 106: ABSTRACT The water, as resource, is
Page 107 and 108: puts in risk large number of person
Page 109 and 110: The main services and problems of w
Page 111 and 112: There are similar problems in diffe
Page 113 and 114: 8.3.3. Energy a. Hydroelectric depe
Page 115 and 116: (chapters 12 and 13), because of th
Page 117 and 118: The main services and problems of w
Page 119 and 120: 9.1. Introduction The emissions of
Page 121 and 122: 9.4. Greenhouse effect The atmosphe
Page 123 and 124: Temperature anomalies (°C) 0.8 0.6
Page 125 and 126: Global climatic change at a global
Page 127 and 128: In view of the unavoidability of th
Page 129 and 130: Background on other regional aspect
Page 135 and 136: Considering the non-linear interact
Page 137 and 138: SST anomalies also have influence o
Page 141: ABSTRACT The purpose of this chapte
Page 145 and 146: Global climate models Table 11.1. B
Page 147 and 148: Global climate models Table 11.2. M
Page 149 and 150: Although changes in weather and cli
Page 151 and 152: Socio-economic variables and also s
Page 153 and 154: Applicability in impact assessments
Page 155 and 156: of the global climate system to the
Page 157 and 158: Climate scenarios B2: Assumes a wor
Page 159 and 160: Climate scenarios The reliability o
Page 161 and 162: Climate scenarios From Table 12.2 i
Page 163 and 164: Climate scenarios Fig. 12.5. The mu
Page 165 and 166: Climate scenarios this would be rel
Page 167 and 168: Results of global circulation model
Page 169 and 170: 13.2.3. Statistical downscaling The
Page 171 and 172: La Plata basin are also considerabl
Page 173 and 174: 10 N EQ 10 S 20 S 30 S 40 S 50 S 10
Page 175 and 176: Regional climatic scenarios Fig. 13
Page 177 and 178: a. Pre-industrial experiment: Initi
Page 183 and 184: Regional climatic scenarios Kalnay,
Page 185 and 186: Low-frequency variability 14.1. Bac
Page 187 and 188: egime occurred during the periods o
Page 189 and 190: Fig. 14.2. As Fig. 14.1, except for
Page 191 and 192: 14.4. SST composites Low-frequency
Page 193 and 194:
Low-frequency variability during th
Page 195 and 196:
Fig. 14.10. As Fig. 14.9, except fo
Page 197 and 198:
Low-frequency variability In genera
Page 199 and 200:
Low-frequency variability Mantua, N
Page 201 and 202:
15.1. Introduction Statistical anal
Page 203 and 204:
Statistical analysis of extreme eve
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
CURRÍCULA OF THE AUTHORS Vicente B
Page 219 and 220:
Curricula of the autors Rubén Mari
Page 221:
Proyect: SGP II 057: “Trends in t
show all

chapter - Atmospheric and Oceanic Science

Create successful ePaper yourself

Delete template?

Save as template?