LISST particle sizes from 11 vertical profiles taken during PolarFront cruise 2022-05

Profile metadata:

Station,Ship_number,Date,Time,Depth,File,Battery

PF1,743,2022-05-20,06:30,370,L1400631,6.7

PF2,750,2022-05-21,04:30,280,L1401804,6.9

T1,774,2022-05-21,22:00,300,L1412158,6.7

PF3,782,2022-05-22,08:00,350,L1420807,6.7

PF4,803,2022-05-22,22:00,360,L1422147,6.6

T2,823,2022-05-24,09:00,260,L1440852,6.7

T3,825,2022-05-24,11:30,215,L1441113,6.7

T4,827,2022-05-24,13:20,200,L1441314,6.6

T5,829,2022-05-24,16:00,190,L1441540,6.6

PF5,832,2022-05-24,18:00,190,L1441818,6.6

PF6,866,2022-05-25,14:30,230,L1451349,6.6

Time is in UTC+02:00

From cruise report (Daase 2022):

PolarFront 2022-05 Laser In-Situ Scattering and Transmissometry (LISST)Emilia Trudnowska, IOPAN

Aim:

To provide profiles of vertical distribution of small size fractions of plankton (3-500um)

To provide an analysis of size structure of small size fractions of plankton (3-500um)

To supplement estimation of productivity of the studied systems based on size spectra theory

MethodA particle size analyser - LISST (Laser In-Situ Scattering and Transmissometry) was used at10 stations in a manner of vertical profiles of the upper 300m in combination with LOPC, WBAT andCTD-F rosette platform.

The LISST-100X instrument is a laser diffraction device. It consists of optics forproducing a collimated laser beam, a specially constructed detector array, electronics for signal pre-amplification and processing, data storage and scheduling computer, and a battery system. The principalmeasurement—angular scattering distribution— is obtained over 32 ring-detectors whose radii increaselogarithmically from 102 to 20,000 microns. This angular range corresponds, respectively, to sizeranges from 2.5 to 500 μm (Type C). The instrument belongs to the consortium of PAN (Polish Academy of Sciences)and was brought to the cruise by Emilia Trudnowska, who is also responsible for data collection andprocessing.

The laser diffraction method for sizing particles was invented in the 1970’s and rapidly becamethe most widely used optical method for determining size distribution for the simple reason that forlaser diffraction, the composition or refractive index of the particles is not important. This methoddetermines size distribution of an ensemble of particles. According to preliminary data analyses, wecould observe distinct particle distribution patterns as well as size distribution between southernmostand northernmost stations.

References

Daase M (ed.) (2022). PolarFront May 2022 Cruise Report. Zenodo. https://doi.org/10.5281/zenodo.7128746