Mesoclimate of the LBA-ECO Santarem Study Area

David FitzjarraldRicardo SakaiOsvaldo MoraesMatt CzikowskyOtavio AcevedoRaimundo Cosme de Oliveira Junior

CD-03 University at Albany, SUNYUniversidade Federal de Santa MariaEMBRAPA Amazonia Oriental

LBA-ECO weather station networkResurrected at the behest of the LBA Science Team (Miami meeting).

Motivation:Determine regional biases/seasonal differences(develop a methodology to determine context inwhich flux observations are made.)

* Study the physical basis for the river breeze

• identify mesoclimatic variabilities:•Cloudiness (incident solar radiation)*Temperature/Humidity* Precipitation

*gasp) support model studies…

*Accommodate the few remaining literalists who use real (vs. reanalysis) data

LBA-ECO STM site special features…

•Large seasonal variation

•High correlation precipitation/ENSO signal

•World class amplitude semidiurnal atm P tide

• Strong influence river breeze/easterly interaction

Recent years in the LBA-ECO STM region:

Pbel

Pbel - Pstm

Tstm Ustm

S O index

Precipitacao

CIRSAN

qsat

Intraannual variability small but important…

Cp T

L q

RH smaller

This presentation from now on:

Focus on diurnal variability ( & seasonal)

Other (continuing) workIdentify inland penetration of River breeze;frequency of occurrence;Gauge seasonal/interannual varibility;Minimize biases in standard climate data.Identify local wind circulations (e.g., Acevedo et al. presentation yesterday.)

Silva Dias et al., 2003

Cloudiness delineates the river….

Moore et al. 2001

Estacoes automaticas: (Campbell Sci.)Medidas: T, RH, K incidente, PAR incidente, T solo, Umidade solo, Pressao superficie, U, direccao,Precipitacao, GPS (relogio).

2 USFS (Keller), upgraded [julho 1998, Belterra, km117]3 LBA-ECO [julho 2000, Jamaraqua, Mojui, Guarana]3 EMBRAPA,upgraded [set 2002, Franca, CG, C-U]

Available hourly data, flux tower km67

Wind rose

Available date km83 flux tower

Hourly data, LBA-ECO weather stations…

River

River

Km 77 flux tower…..

wind rose

km67

km67

Local sites always make a difference in windobservations.

Fujita Transmission Factors, LBA-ECO WX stations.

km117 pasture siteJamaraquaTapajos site

River sites

Incident global short-wave radiation

Vila Franca

Specific humidity, double peaks show CBL birth/death

Std deviation of wind direction—separating theconvective portion of the day….

Jamaraqua

Franca

Cacoal Grande

2 C

River stations

Maximum wind events….k 2001 350 1300 7.28j 2003 84 1330 7.74m 2001 204 0220 7.11g 2002 19 1200 6.81c 2001 54 1700 6.44s 2003 37 2000 3.94f 2002 68 1000 4.22e 2002 208 0430 9.91

River

From Silva Dias et al., 2003

Sodar, Santarem airport…….

NCL

NCLriverObserver report..

…and also look at interannual differences in theOnset of the wet season.

NO clouds at night, dry season….

From before……

Radiative consequences of cloud cover…

River stations

Standard deviation of global solar radiation….

qsat

(See CD-03: Czikowsky et al. poster for details on the ceilometer observations at km67)

The “natural clock” of the tropics….

River breeze mesoscale pressure gradientcan extract from station data; lookslike model simulation results—(Silva Dias et al., 2003)

River-inland differences:2 C temperature bias

20% cloud reduction in Kdn

Still searching for the precipitation signal

River breeze expressed actively for slack easterly cases.

Cloud base determined by thermodynamics in cleared areas.

Nocturnal winds appreciable only along river(a counter-current nocturnal river of air)

River convective day and night.

Balao cativo –estudos no futuro……