LGK GF777 Clase 8: La atmósfera cambiante: una perspectiva sistémica Paradigmas y métodos GF 777 Otoño 2002

LGK GF777 Contenidos de hoy Integrando observaciones y modelación Observaciones y mediciones Modelación Paradigmas y métodos para abordar la ciencia y la gestión de la atmósfera cambiante (Ejemplo: INDOEX) Ejercicio “(to be) made in Chile”

LGK GF777 Modelación Mediciones

LGK GF777 Mediciones In situ Percepción remota Laboratorios Campañas...Procesos Monitoreo...Tendencias

LGK GF777 Módulos químicos Módulos meteorológicos Métodos numéricos y resolución de EDP Datos de entrada Implementaciones computacionales Evaluación y validación CI/CB

LGK GF777 VALIDACIÓN: Comparación sistemática contra observaciones Intercomparación Análisis de sensibilidad

LGK GF777 INDOEX is a $25M international experiment with contributions from over 60 institutions from 13 nations

LGK GF777 Greenhouse Warming or Aerosol Cooling? "The balance of evidence suggests a discernible human influence on global climate.“ (IPCC, 1994) The project's goal is to study natural and anthropogenic climate forcing by aerosols and feedbacks on regional and global climate.

LGK GF777 Objetivos principales Assess the significance of sulfates and other continental aerosols for global radiative forcing. Assess the magnitude of solar absorption in ITCZ cloud systems. Assess the role of the ITCZ in the transport of trace species and pollutants.

LGK GF777 Y de pasada...(Targets of Opportunity ) Meteorology of the Asian winter monsoon period Indian Ocean warm pool SST regulation Microphysical and radiative properties of cirrus clouds

LGK GF777 Grupos de trabajo

LGK GF777 Los responsables.. T.N. Krishnamurti 8 J. Kuettner 6 J. Lelieveld 9 S.C. Liu 10 A.P. Mitra 11 J. Prospero 12 R. Sadourny 13 A.F. Tuck 10 F.P.J. Valero 14 Authors V. Ramanathan 1 P.J. Crutzen 1,2 M.O. Andreae 2 J. Coakley 1,3 R. Dickerson 1,4 J. Heinzentberg 5 A. Heymsfield 1,6 J.T. Kiehl 1,6 D. Kley 1,7

LGK GF777

Lelieveld, J., P.J. Crutzen, V. Ramanathan, M.O. Andreae, C.A.M. Brenninkmeijer, T. Campos, G.R. Cass, R.R. Dickerson, H. Fischer, J.A. de Gouw, A. Hansel, A. Jefferson, D. Kley, A.T.J. de Laat, S. Lal, M.G. Lawrence, J.M. Lobert, O. Mayol-Bracero, A.P. Mitra, T. Novakov, S.J. Oltmans, K.A. Prather, T. Reiner, H. Rodhe, H.A. Scheeren, D. Sikka and J. Williams, The Indian Ocean Experiment: Widespread Air Pollution from South and Southeast Asia. Science, 291(5506):1,031-1,036.

LGK GF777 Rapa Nui STE processes and their impact on the O 3 balance in the subtropics of the Southern Hemisphere: A multi- scale integrated study based at Cerro Tololo (30ºS, 70ºW, 2200 m.a.s.l) CIALS/CMM/DMC

LGK GF777 At Cerro Tololo (30ºS, 70ºW, 2200 m.a.s.l.), continuous measurements of surface ozone (O 3 ), radiation and meteorological parameters have been performed since early 1996 under the auspices of the World Meteorological Organization (WMO) and through the Chilean Weather Office in cooperation with the Interamerican Southern Astronomical Observatory. This station belongs to a set of background regional stations intended to survey global change that are run under the Global Atmospheric Watch (GAW) program of the WMO. The chemical composition of the air arriving at the Cerro Tololo site appears to be generally representative of background conditions of free-tropospheric air in the subtropics of the Southern Hemisphere (SH). The O 3 data collected at Tololo show a seasonal variation with maximum mixing ratios in late winter and spring, which appear to be related with the intrusion of O 3 -rich air in connection with the tilting of isentropic surfaces near the subtropical jet stream (SJT). Cut-off lows and deep troughs appear also to be major contributors to the O 3 measured at Cerro Tololo. Stratosphere- troposphere exchange (STE) processes are key factors for the balance of the radiatively and chemically important trace species (e.g., O 3 ). STE processes seem also crucial for the formation of new particles. Moreover, these processes up-wind of the Andes barrier play a key role for the occurrence of heavy precipitation events over Central and Northern Chile. Despite their importance, STE processes are still poorly understood, particularly over the SH. Hereby, we propose a study intended to assess STE processes over Cerro Tololo in the subtropics of the SH by means of an integrated approach that includes in situ measurements as well as regional and meso-scale modeling. Our aim is to identify the mechanisms that explain the O 3 spring maximum at Tololo. Also, we want to assess the relative importance of the mechanisms responsible for the transport of O 3 -rich air from intrusion areas, where STE occurs, to the Tololo site, i.e., advection, large-scale subsidence and turbulent mixing. To identify characteristic patterns of STE, a climatology of typical air-masses arriving at Tololo will be built-up on the basis of composite analyses of reanalysis data using potential vorticity (PV), water vapor and the like as STE proxies. Further details will be identified by using high-resolution (ca. 0.1º, 3 hourly) climatological fields, dynamically interpolated from reanalysis data for nine months in the years 1997, 1998, 1999 and 2000, which cover typical meteorological situations over the Tololo area, including El Niño and La Niña years. In situ vertical soundings of O 3 will be carried out three times a day, daily during a 10-days long campaign in the spring of 2004 at Tololo. Complementarily, meteorological soundings will be performed during the campaign. Also, measurements of a beryllium isotope ( 7 Be), sampled for 24 hours every three days along one year, and carbon monoxide (CO), continuously sampled during the campaign, will be concurrently performed in order to discriminate the origin of air masses. Regional and meso-scale numerical simulations of stratospheric intrusions as expressed in dynamical variables (e.g., PV) and in transport of an O 3 -like tracer will be performed. These simulations will be done for typical spring conditions as identified by the climatological data and for selected events according to the data collected during the campaign. Meteorological models will be used to produce dynamically interpolated three-dimensional (3-D) regional and meso-scale meteorological fields, which will drive a 3-D Eulerian transport model that will simulate the intrusion and subsequent dispersion of an O 3 -like tracer subject to photolysis and dry deposition. The simulations will be evaluated against in situ and available satellite measurements of O 3, water vapor and other relevant STE tracers.

LGK GF General objective  To identify the mechanisms that explain the seasonal variation and spring maximum in O 3 mixing ratios in the subtropics of the SH, particularly at the Tololo GAW regional station 1.2. Specific objectives  To contribute to the characterization of the origin of the air masses observed at the Tololo GAW station  To identify characteristic patterns of STE over Cerro Tololo in connection with the tilting of isentropic surfaces near the subtropical jet stream (SJT) and cut-off lows and deep troughs that affect the area.  To document the vertical distribution of ozone in the subtropics of the SH off the coast of South America and the Andes barrier, particularly for late winter and spring  To assess the relative importance of the mechanisms responsible for the transport of O 3 -rich air from intrusion areas where STE occurs to the Tololo site, i.e., advection, large-scale subsidence and turbulent mixing.  To validate the representation of STE in regional and meso-scale meteorological and Eulerian transport models  To perform sensitivity analyses with respect to advection and diffusion (turbulent mixing) numerical schemes

LGK GF777 Global NWP model ECMWF/NCEP-NCAR Regional NWP model RCA/HIRLAM/MM5 Boundary conditions 6 hours, T, q, u, v, SST,... T, u, v, q, CLW, CC, prec,.. Tracer’s distribution, deposition, etc. Dispersion model MATCH Meso-scale meteorological model KAMM T, u, v, q, CLW, CC, prec,..

LGK GF777 ECC O 3 sensor u,v,T, etc Surface measurements of: O 3, CO, 7 Be, UV u,v,T, etc

LGK GF777 Ejercicio: Evaluar el proyecto Juan Quintana lo defiende Los demás hacen de abogados del diablo ¿Es este un enfoque sistémico?

LGK GF777 Próxima semana Borrador de trabajo y esquema de presentación Tareas corregidas (!) y última tarea (se entrega el día del examen)