LALINET STATUS-STATION EXPANSION AND LIDAR RATIO SYSTEMATIC MEASUREMENTS

LALINET is expanding regionally to guarantee spatial coverage over South and Central Americas. One of the network goals is to obtain a set of regional representative aerosol optical properties such as particle backscatter, extinction and lidar ratio. Given the North-South extension and influence of distinct airmass circulation patterns it is paramount to distinguish these optical parameters in order to gain better perfomance in radiation transfer models. A set of lidar ratio data is presented.


INTRODUCTION
Latin America Lidar Network is a federative fully operative lidar for aerosol research in South and Central America.Its operational cycle concerns probing the atmosphere on regular basis to retrieve vertically and temporally resolved aerosol optical and microphysical properties (Luis Guerrero-Rascado et al., 2016).Most of the instruments based in the network were customized and produced configurations suitable for the aerosol observation task.The network was officially established in 2013 by recognition as being part of GAW-GALION programs under the supervision of World Meteorological Organization (Antuña-Marrero et al., 2016).The present goals of LALINET are: 1. Consolidate the measurement and data acquisition protocols Yet regarding the vast majority of stations share a collocated AERONET station the use of the GRASP approach is also envisaged (Torres et al., 2016) in order to obtain particle microphysical properties.Currently LALINET is seeking its expansion to better cover up a region roughly twice the size of EARLINET (Mona, L. et al., 2016) and therefore a region where more circulation patterns take place.A careful establishment of a regional distributed aerosol optical parameter database pose a challenge wich could be tackled with the network expansion.In this matter 2 stations were deployed as seen in table 1.One in Natal, Brazil, which should be focused on long-range aerosol transport from Saharan dust.The other in Punta Arenas in Chile, which is also part of SAVER.NET (Quel, Eduardo et al., 2016) which merges the efforts of LALINET and AD-NET (Nishizawa, Tomoaki et al., 2016).

LALINET Lidar Stations
Up to date there are 14 operative stations, see Table 1, distributed along the South american continent.The vast majority has collocated AERONET sunphotometer stations which helps in the lidar data retrieval of the lidar ratio by means of a closure between the two instruments and further on the implementation of data integration algorithms such as GRASP.

METHODOLOGY
LALINET measurement protocol follows an twice a week measurements on Mondays and Thursdays, even though pne station operates continuously (MAO) and with other schedules for other proposes.The products obtained are aerosol backscattering and extinction profiles, Lidar ratios (average and profiles when raman channels are operative).Since the vast majority of stations have collocated AERONET sunphotometers it is possible to obtain microphysical products.Some of the station also have polarization-sensitive channels which allows information on shape and identification of aerosols.

Calbuco Eruption
On April 22, 2015, the Calbuco volcano in Chile (41.33 o S, 72.62 o W) erupted after 43 years of inactivity, followed by an injection of pyroclastic material dispersed into the atmosphere on weeks after the event.At first a threat-alarm to aviation traffic and air quality over a large area was released, and the stations on the southermost part of SA were triggered on daily monitoring basis in Argentina, Brazil, and Chile.Below we find a temporal serie of range corrected signal at 532 nm the quick look of the lidar measurements conducted at AEP station, in Buenos Aires, Argentina.The volcanic layer detected on April 24 shows a persistency along the entire day ranging between 5 and 7 km Later on there is a subsidency of this layer not mixing however with the urban mixing layer below the PBL around 1.5 -2.0 km.This station, to the east of the Calbuco, measured a tropospheric aerosol layer at about 6 km a.g.l. which subsided along the day of measurement.

Lidar Ratio Evaluation
Aiming to create a consistent lidar ratio climatology regionally distributed we have evaluated the yearly mean values of some LA-LINET stations which included the results obtained from procotol measurements taken routineously.Some of the values are from intensive campaigns taken previously (BUE and PAR) using lidar/sunphotometer sinergy in clear sky conditions.All LR"s are at 532 nm except MAO (355 nm).The standard deviations at each value are about 10 − 15%.

CONCLUSIONS
LALINET is in expansion and working to reach good standards and practices for regional monitoring of aerosols and trace gases in South and Central America.The network now comprehends 14 operative stations.The network has been capable of monitoring events under a routine and obtaining aerosol optical properties with regional representation and sparse events such as volcanic eruptions.Network capabilities are also under scrunity to comply with QA/QC protocols.

Figure 1 :
Figure 1: RCS quicklook obtained by AEP station, in Buenos Aires, Argentina, 2 days after the Calbuco Eruption allowing a consistent tracking of the pyroclastic material ejected by the volcano spreading over south of South America.

Figure 2 :
Figure2: Lidar Ratios at some of LALINET's stations.These values should be updated and extended to other stations in order to have a regional representative values.

Table 1 :
LALINET Lidar Stations -The boxes in green are newly added stations in 2016.*Temuco station is the previous Concepcion Station.