ALBERT

Description: Aerosol and rain sampling in two size fractions was carried out at a rural site located on the coast of the eastern Mediterranean, Erdemli, Turkey (36∘33′54′′ N, 34∘15′18′′ E). A total of 674 aerosol samples in two size fractions (337 coarse, 337 fine) and 23 rain samples were collected between March 2014 and April 2015. Samples were analyzed for NO3-, NH4+ and ancillary water-soluble ions using ion chromatography and water-soluble total nitrogen (WSTN) by applying a high-temperature combustion method. The mean aerosol water-soluble organic nitrogen (WSON) was 23.8 ± 16.3 nmol N m−3, reaching a maximum of 79 nmol N m−3, with about 66 % being associated with coarse particles. The volume weighted mean (VWM) concentration of WSON in rain was 21.5 µmol N L−1. The WSON contributed 37 and 29 % to the WSTN in aerosol and rainwater, respectively. Aerosol WSON concentrations exhibited large temporal variation, mainly due to meteorology and the origin of air mass flow. The highest mean aerosol WSON concentration was observed in the summer and was attributed to the absence of rain and resuspension of cultivated soil in the region. The mean concentration of WSON during dust events (38.2 ± 17.5 nmol N m−3) was 1.3 times higher than that of non-dust events (29.4 ± 13.9 nmol N m−3). Source apportionment analysis demonstrated that WSON was originated from agricultural activities (43 %), secondary aerosol (20 %), nitrate (22 %), crustal material (10 %) and sea salt (5 %). The dry and wet depositions of WSON were equivalent and amounted to 36 % of the total atmospheric WSTN flux.

Description: Charge-coupled device (CCD) spectrometers are widely used as detectors in analytical laboratory instruments and as sensors for in situ optical measurements. However, as the applications become more complex, the physical and electronic limits of the CCD spectrometers may restrict their applicability. The errors due to dark currents, temperature variations, and blooming can be readily corrected. However, a correction for uncertainty of integration time and wavelength calibration is typically lacking in most devices, and detector non-linearity may distort the signal by up to 5% for some measurements. Here, we propose a simple correction method to compensate for non-linearity errors in optical measurements where compact CCD spectrometers are used. The results indicate that the error due to the non-linearity of a spectrometer can be reduced from several hundred counts to about 40 counts if the proposed correction function is applied.

Description: Two-sized aerosol and rain sampling were carried out at a rural site located on the coast of the Eastern Mediterranean, Erdemli, Turkey (36°33′54″ N and 34°15′18″ E). A total of 674 aerosol samples in two size fraction (coarse = 337; fine = 337) and 23 rain samples were collected between March 2014 and April 2015. Samples were analyzed for NO3−, NH4+ and ancillary water-soluble ions by Ion Chromatography and water-soluble total nitrogen (WSTN) by applying a High Temperature Combustion Method. The mean aerosol WSON was 23.8 ± 16.3 nmol N m−3, reaching a maximum of 79 nmol N m−3, with about 66 % being associated with coarse particles. The volume weighted mean (VWM) concentration of WSON in rain was 21.5 µmol N L−1. The WSON contributed 37 % and 29 % to the WSTN in aerosol and rainwater, respectively. Aerosol WSON concentrations exhibited large temporal variations mainly due to rain and the origin of air mass flow. The highest mean aerosol WSON concentration was observed in the summer and was attributed to the absence of rain and re-suspension of cultivated soil in the region. The mean concentration of WSON during dust events (38.2 ± 17.5 nmol N m−3) was 1.3 times higher than that of non-dust events (29.4 ± 13.9 nmol N m−3). Source apportionment analysis demonstrated that WSON was originated from agricultural activities (43 %), secondary aerosol (20 %), nitrate (22 %), crustal (10 %) and sea-salt (5 %). The dry and wet depositions of WSON were equivalent and amounted to 36 % of the total atmospheric WTSN flux. Considering the Cilician Basin, the atmospheric water-soluble nitrogen flux would sustain 33 % and 76 % of the new production in the associated coastal and open waters, respectively.