Boundary layer component (RACCI -SG3)

Estratégia de coleta de dados 4 sítios experimentais de RS (Abracos, Rebio Jaru, Porto Velho e Guajará-Mirim) Sondagens as 00, 06, 12 e 18 GMT e especiais (09,15,18 e 21 GMT) Fase I: de 15 a 30/9 de 2002 Fase de transição: de 1 a 15/10/2002 Fase II: de 15 a 30/10/2002

Estatísticas de RS Abracos: 214 sondagens Rebio Jaru: 125 Porto Velho: 110 Guajará-Mirim:143 Sondagens HSB (GM): 36 sondagens

Balão cativo içamento noturnos (das 17 as 09 horas) a partir do dia 17/10, içamentos em horários variados (dependendo das condições meteorológicas)

Setembro 2002

Outubro 2002

Série temporal da precipitação ABRACOS

Fluxos de Calor sensível – períodos I e II

Série temporal das alturas h  e h q A camada limite convectiva caracteriza-se por possuir suas propriedades bem misturadas (em termos de  e de q), sendo a altura determinada pelos critérios:   /  z < 2 K/km  q /  z < 2 g/kg/km

Precipitação -Ariquemes

Chuva Convectiva – ABRACOS

Perfis de temperatura e umidade Preto- 14 UTC, azul – 17 UTC e vermelho-21 UTC (19/10/2002)

Influência da chuva (27/9/2002) – pastagem

Influência da chuva 28/09/2002

Elementos climáticos

Cooling and moistening due to a strong rainfall event (28/09/2002)

NBL (23/09/20002)

NBL (6 GMT 24/09/2002)

Perfis de temperatura e umidade (23 e 24/09)

Sodar - ABRACOS

Imagem satélite (24/09/2002)

Seria convecção local??

PV (vermelho) e GM (azul) sondagem das 06/09/2002 as 600 UTC RS em PV e GM

Height CBL = 2000 m (18/09/2002)

Height CBL = 2300 m 20/09/2002

Série temporal da altura CLC - seco (19-22/09/02)

Série temporal de aerossóis – abracos

Formação de Recursos Humanos (1/4) Mestrado (Luiz André dos Santos – INPE) que está analisando as diferentes características termodinâmicas observadas na pastagem (período muito seco, chuvas durante a tarde e início de noite, formação de camadas rasas de CLC após ocorrência de chuvas, etc) (bolsista CAPES)

Formação de Recursos Humanos (2/4) Iniciação Científica (Eric L. Barroso – ITA). Eric está determinando as alturas da CLC em todos os experimentos já realizados (ABRACOS/RBLE, LBA/TRMM, LBA/RACCI) e classificando as alturas em diferentes condições (seco, chuvoso, pertubado, não-pertubado). Bolsista CNPq-IMilenio). Cooperação Íria Vendrame-ITA

Formação de Recursos Humanos (3/4) Iniciação Científica (Paulo Cezar Hanoka – ITA). Hanaoka está determinando a distribuição de chuvas em Rondonia (rede de pluviometros) durante LBA/TRMM e do LBA/RACCI. Bolsista CNPq-Imilenio. Cooperação Profa. Iria Vendrame-ITA

Formação de Recursos Humanos (4/4) Doutorado (Rosa do Nascimento Santos - INPE). Rosa está analisando a estrutura da Camada Limite Noturna em Rondônia (LBA/TRMM) através de análises observacionais e de modelagem. Doutorado Sandwich (Universidade Free Amesterda – Prof. Dolman). Bolsista CAPES

"Nocturnal boundary layer (NBL) measurements in Rondonia" Experimental Area Experimental Area SITES Rolim de Moura (RM) – pasture site Rebio Jaru (Forest) Faz. N. S ra (FNS) – pasture site PERIOD FEB/1999 Wet Season

Mean values of NBL depth – hi, potential temperature on the nocturnal inversion basis –  (i), layer specific humidity – q, NBL strength – i.) LBA – Fazenda N. S. a (pasture) Local timeh i  (i)q (g.kg -1 )  S ii.) LBA – Rebio Jaru (forest) Local timeh i  (i)q (g.kg -1 )  S iii.) LBA - Rolim de Moura Local timeh i  (i)q (g.kg -1 )  S

Transition times and NBL break down Transition times and NBL break down Large differences between the total heat flux released by surface (forest, RM and FNS) and biomass (forest), and the heating integrated from the potential temperature in the 3 sites - No balance Sensilble H (Forest, FNS and RM), biomass heatflux, B (Forest), total heat integrated for the NBL break up period and; boundary layer heating, . Forest DateLocal TimeH (W.m -2 )B (W.m -2 )Total heat flux (m.K)  (m.K) 12/0206: : /0207: : Rolim de Moura DateLocal TimeH (W.m -2 )Total heat flux (m.K)  (m.K) 09/0206: : /0205: : /0206: : Fazenda N. S. a DateLocal TimeH (W.m -2 )Total heat flux (m.K)  (m.K) 14/ / / In general,  was lower than Total heat flux (m.K) measured by eddy correlation system. Smallest differences in the Forest and highest ones in FNS

Low-level atmospheric jets (Boundary Layer Jets), or Nocturnal Jets - NJ Low-level atmospheric jets (Boundary Layer Jets), or Nocturnal Jets - NJ DEFINITION: A jet stream occurring in a height below of 1-2 km from the surface, also known as Nocturnal Jet (NJ) because is a common phenomenon under the nighttime stable conditions taking part of the NBL structure and dynamic FEATURES: -Wind speed profile showed a local maximum with minimum velocity value of 7 m.s -1 and that was at least 1.5 m.s -1 higher then the speeds both above and below it. - Jet Core occurrence below of the firsts 1000 m STATISTICS: radiosonde wind profiles - 50 profiles showed a NJ configuration - Most of cases isolated events observed during one single sounding CASES RM11 Forest16 FNS23

- Jet core below 600 m - ~ 58% of cases - 86% presented wind speed below 10 m.s -1 - Jet Core prevailing direction - Southerly Nocturnal jet statistic as observed in Rondônia, during the wet season: i) height of the Jet Core (z j ); ii) wind speed at the Jet Core (V j )

Comparação RASS x RS

Produção Científica Apresentação de um poster no Int. Conference on Earth System Modelling (Hamburgo Sept 15-19, 2003) Apresentação de um poster no XIII Congresso Brasileiro de Agrometeorologia (Santa Maria Ago 3-7,2003)

Observational aspects of the convective boundary layer at pasture site in Amazonia during LBA/RACCI 2002 G. Fisch, L.A.T. Machado, M.A.F. Silva Dias, R. F. Lyra and A.J.Dolman Centro Técnico Aeroespacial The experimental site was a deforested area (pasture) in the Ji-Paraná Rondônia State, southwest of Amazônia. The experiment was held during Sept (dry period) and Oct 15-30, 2002 (wet period) and it consists of rawinsoundings launched at 8, 11, 14 and 17 Local Time (LT). The soundings were made with a Vaisala device (RS80-15G) that measures the profiles of air temperature, pressure, relative humidity and winds (using GPS techniques) up to 20 km (Figure 1 – map, sonde RS80 and pasture scenarious). This study was supported by Brazilian Agencies (CNPq, CAPES and FAPESP) The Amazon region is an important source of heat and water vapour for the atmosphere and plays a significant role in the general circulation of the atmosphere. In the last decades, this region is receiving attention from the world scientific community as it has a key impact on the energy and CO2 budget of the planet. This region is suffering a high rate of deforestation and tropical forest has been replaced by pasture and agricultural crops. The latest figures from INPE estimated that approximately 13% of the pristine forest had been converted, mainly in Para and Rondonia State. The RACCI 2002 (Radiation, cloud and climate interactions in the Amazon during the DRY-TO-WET transition season) part of the LBA Project ( investigates the role of the aerosols in triggering the moist convection and also influencing the onset of the rainny season. The aim of this paper is to study the growth of the convective boundary layer over a pasture site in Amazonia during the LBA/RACCI experiment Introduction 2. Data and site 3. Results Table I: Height and thermodynamic characteristics (potential temperature -  and specific humidity - q) during the dry (20-29 Sept) and wet (23-29,Oct,2003) periods. Figure 2: Potential Temperature (left) and Specific Humidity (right) for 11 LT (black), 14 LT (blue) and 17 LT (red) on Sept 28,2002. The radar scope is in the right 3.2 The structure of the CBL and its modification by the rain At the end of the dry season there was some strong showers like Sept 28, 2002 (38 mm in 3 hours). Before the rain (11 LT) the CBL is very active and well mixed and the height was 1200 m. This structure was totally destroyed by the rain which happens before 14 LT sounding, producing the cooling of the atmosphere and a stable layer. After the rain the solar radiation heats the surface but the thermal inversion was not eroded anymore (Figure 2). 3.3 The Low level Jet event During the night of Sept 24, 2002 a low level jet event has occured with strong winds (around 11 m/s at 500 m). This LLJ was probably due to the coupling between an ocluded frontal system in the SE Brazil and the organized convection in Amazonia. This LLJ provokes a strong vertical mechanical mixing that produces an unexpected shallow mixed layer (height of 400 m). The role of this ML in transfering trace gases throughout the residual layer is being under investigation (Figure 3). Figure 3: The potential temperature (left) and windspeed (right) for Sept 23 (blue) and Sept 24 (red). Sodar data at the top

Trabalhos futuros Avaliação das características da CL em condições “sujas” e “razoavelmente limpas” nos sítios de floresta e pastagem Características termodinâmicas e dinâmicas da CL para iniciar convecção e chuva na pastagem Modificações da estruturas da CL em condições de chuva na pastagem Evolução das CLs convectiva e estável nos sítios de floresta e pastagem durante o LBA dry-to-wet Estudos de casos da estrutura da CL noturna na pastagem Ocorrência de jatos de baixos níveis e sua implicação na estrutura da CL noturna