The Arctic Turbulence Experiment 2009 - additional laser Scintillometer measurement campaign 2009 at the Bayelva catchment on Svalbard: Technical documentation and visualization of the near surface measurements during the ARCTEX-2009 campaign, August, 10th to August, 20th 2009

UNIVERSITY of BAYREUTH Department of Micrometeorology The Arctic Turbulence Experiment 2009 Long-term measurements of near-surface turbulent fluxes in the Arctic environment - additional laser Scintillometer measurement campaign 2009 at the Bayelva catchment on Svalbard (ARCTEX-2009) Technical documentation and visualization of the near surface measurements during the ARCTEX 2009 campaign August, 10th to August, 20th 2009 Johannes Lüers Jörg Bareiss Martin Wagner Work Report No. 49 Bayreuth, Feb 2012 2 Arbeitsergebnisse, Universität Bayreuth, Abt. Mikrometeorologie Work Report University of Bayreuth, Dept. of Micrometeorology Print, ISSN 1614-8916, Internet, ISSN 1614-8924 http://www.bayceer.uni-bayreuth.de/mm/ Eigenverlag: Universität Bayreuth, Abt. Mikrometeorologie Vervielfältigung: Druckerei der Universität Bayreuth Herausgeber: Prof. Dr. Thomas Foken Universität Bayreuth, Abteilung Mikrometeorologie D-95440 Bayreuth Die Verantwortung über den Inhalt liegt beim Autor. 3 Contents 1 Introduction.......................................................................................................................4 2 General Information..........................................................................................................5 2.1 Location....................................................................................................................5 2.2 Surface and weather conditions ...............................................................................7 3 Overview of measurement sites .......................................................................................8 3.1.1 Meteorological tower AWI Ny-Ålesund (MT).....................................................9 3.1.2 Bayelva Eddy-Flux measurement complex AWI (EF).....................................10 3.1.3 University of Bayreuth Laser Scintillometer (SLS)..........................................11 3.1.4 Bayelva Permafrost Station AWI (BPS)..........................................................12 4 Detailed description of instrumentation ..........................................................................13 4.1 Meteorological tower AWI (MT) ..............................................................................13 4.2 Eddy-flux measurements (EF)................................................................................13 4.3 Laser Scintillometer (SLS)......................................................................................13 4.4 Bayelva Permafrost Station AWI (BPS)..................................................................14 5 Data acquisition and recording.......................................................................................15 5.1 Laser Scintillometer (SLS)......................................................................................15 5.2 Eddy-flux data (EF), Bayelva Permafrost Station AWI data (BPS) and Meteorological tower AWI data (MT)..................................................................................15 6 Visualization of standard meteorological measurements ...............................................16 6.1 Synoptic situation ...................................................................................................16 6.2 Entire observation period........................................................................................31 6.3 Daily charts.............................................................................................................41 7 Visualization of directly measured turbulence fluxes......................................................57 7.1 Calculation of turbulent fluxes with the software package TK21 ............................57 7.2 Entire observation period........................................................................................58 7.3 Daily charts.............................................................................................................71 8 Archived Data (CD, DVD, HDD).....................................................................................74 4 1 Introduction Accurate quantification of turbulent fluxes between the surface and the atmospheric boundary layer in polar environments, characterized by frequent change of weather and exchange conditions (stable to very stable or intermittent; rapid, short term neutral to unstable stratified conditions) is a fundamental problem in soil-snow-ice-vegetationatmosphere interaction processes. The observed rapid climate warming in the Arctic requires improvements in the permafrost and carbon cycle monitoring. To address these problems, it is essential to improve the databases with high-quality in-situ measurements of turbulent fluxes above tundra landscape surfaces applying the Eddy-Covariance method and the laser scintillometry. Results from the Arctic Turbulence Experiment 2006 on Svalbard helped to better understand physical exchange processes of energy and matter transport and to improve instrumentation standards as well as quality assessment techniques (Lüers and Bareiss 2010, 2011; http://www.arctex.uni-bayreuth.de). Therefore, the primary goal of this additional laser scintillometer measurement campaign is to estimate the flux contributions covering typical tundra surfaces across the Bayelva catchment during a summer season south-west of the Ny-Ålesund village, Kongsfjord, Svalbard. This effort makes it possible to define the spatial context of the fluxes, and to include land use features of the surrounding terrain in the quality assessment of all observations in the Bayelva catchment over the last 10 years performed by the Alfred Wegener Institute for Polar and Marine Research (AWI). The primary goals of this ARCTEX-campaign were: 1. continuous measurements of high-resolution (20 Hz) turbulent heat fluxes near the tundra surface using an ultra sonic anemometer (eddy-covariance method) and an open path CO2/H2O infrared gas analyzer, 2. continuous measurements of the turbulent sensible heat flux near the tundra surface using the laser scintillometry, 3. measurements of standard meteorological data sampled at 1 minute intervals using the AWI meteorological tower (2 m and 10 m) and 30 minute intervals using the Bayelva Permafrost Station from the AWI, 4. preand postprocessing of high-quality data sets of turbulent fluxes using state of the art flux data quality assessment techniques, 5. understanding of exchange processes and their parameterization for neutral and stable conditions. Lüers, J; Bareiss, J: Direct near-surface measurements of sensible heat fluxes in the arctic tundra applying eddy-covariance and laser scintillometry - The Arctic Turbulence Experiment 2006 on Svalbard (ARCTEX-2006), Theoretical and Applied Climatology, 105, 387-402 (2011) Lüers, J; Bareiss, J: The effect of misleading surface temperature estimations on the sensible heat fluxes at a high Arctic site – the Arctic turbulence experiment 2006 on Svalbard (ARCTEX-2006), Atmospheric Chemistry and Physics , 10(1), 157-168 (2010) 5 2 General Information 2.1 Location The Bayelva climate and soil monitoring site is located in the Kongsfjord region at the west coast of the Svalbard Island. The observation site is part of the Brøgger peninsula, and located in the Bayelva River catchment, about 3 km from the village of Ny-Ålesund (78°55'N, 11°50’E). The terrain of the Bayelva catchment is bordered eastward by hilly tundra and in the southeast by the Zeppelin Mountain (554 m). From south to southwest the 655 m high Brøgger Mountain and the two flanks of the Brøggerbreen glacier ending into moraine rubble and the Bayelva riverbed. The Bayelva River is even located in the west of the measurement place with its bed mainly consisting of sand and gravel. The southwest border is the 695 m high Schetelig Mountain. To the north of the measurement place the terrain is flattening and at about 1 km distance the Bayelva River reaches the shore line of the Kongsfjord (Arctic Ocean). In the catchment area sparse vegetation alternates with exposed soil and sand and rubble fields. Typical permafrost features, such as mud boils and non-sorted circles, are found in many parts of the study area. The Bayelva permafrost site itself is located at 25 m above mean sea level, on top of the small Leirhaugen hill and the eddy-flux complex is positioned southward half way down the slightly inclining (< 5°) slope (Westermann et al., 2009). The dominant ground pattern at the study site consists of non-sorted soil circles which were formed after the last glacial period. The bare soil circle centers are about 1 m in diameter and are surrounded by a vegetated rim consisting of a mixture of low vascular plants of different species of grass (Carex spec., Deschampsia spec., Eriophorum spec., Festuca spec., Luzula spec.), catchfly, saxifrage, willow and some other local common species (Dryas octopetala, Oxyria digyna, Polegonum viviparum) and unclassified species of mosses and lichens (Ohtsuka et al., 2006). The vegetation cover at the measurement site was estimated to be approximately 60%, the remainder being bare soil with a small proportion of stones (Lloyd et al., 2001). The silty clay soil has a high mineral content, while the organic content is low, with volumetric organic fractions below 10% (Boike et al., 2008). The fetch area close to the eddy-flux complex is characterized by dry tundra. The covering of the soil with mud boils increases and the structure of the vegetation is changing slightly to a shorter growth height with a maximum of 5 cm to 10 cm. The Bayelva station has provided a long-term record of climatological parameters and permafrost temperatures since 1998 and eddy-flux data from 2008. At present, the permafrost at Leirhaugen hill is relatively warm, with a mean annual temperature around −2 °C at 1.5 m depth. The maximum active layer depth in summer 2008 was on the order of 1.5 m. Westermann S., J. Lüers, M. Langer, K. Piel, and J. Boike (2009), The annual surface energy budget of a high-arctic permafrost site on Svalbard, Norway, The Cryosphere, 3, 245-263. Ohtsuka, T., M. Adachi, M. Uchida, and T. Nakatsubo (2006), Relationships between vegetation types and soil properties along a topographical gradient on the northern coast of the Brøgger Peninsula, Svalbard, Polar Bioscience, 19, 63-72. Lloyd, C.R., R. J. Harding, T. Friborg, and R. Aurela (2001), Surface fluxes of heat and water vapour from sites in the European Arctic, Theor. Appl. Climatol., 70, 19-33. Boike, J., O. Ippisch, P. Overduin, B. Hagedorn, and K. Roth (2008), Water, heat and solute dynamics of a mud boil, Spitsbergen, Geomorphology, 95, 61-73. 6 Detailed geographic locations of the “Arctic Turbulence Experiment 2009” (ARCTEX-2009) at the Bayelva catchment 3 km west of Ny-Ålesund (Svalbard, Kongsfjorden); August 2009, University of Bayreuth, Germany. General location Svalbard, Kongsfjorden, Ny-Ålesund, Position (Center of settlement): 078° 55’ 24’’ N, 011° 55’ 15’’ E Scintillometer UBT01 dry Tundra (SLSdry), Bayelva: Coordinates: 078° 55’ 24’’ N, 011° 49’ 55’’ E (Transmitter) 078° 55’ 22’’ N, 011° 49’ 42’’ E (Receiver) Altitude: 16 m a. s. l. Land use: dry Tundra Scintillometer UBT02 wet Tundra (SLSwet) , Bayelva: Coordinates: 078° 55’ 27’’ N, 011° 49’ 53’’ E (Transmitter) 078° 55’ 25’’ N, 011° 50’ 07’’ E (Receiver) Altitude: 14 m a. s. l. Land use: wet Tundra Bayelva Eddy-Flux complex AWI (EF): Coordinates: 078° 55’ 17’’ N, 011° 49’ 51’’ E Altitude: 18 m a. s. l. Land use: dry Tundra Bayelva Permafrost Station AWI, (BPS) Coordinates: 078° 55’ 15’’ N, 011° 49’ 59’’ E Altitude: 25 m a. s. l. Land use: Tundra Bayelva Meteorological tower AWI (BMT): Coordinates: 078° 55’ 18’’ N, 011° 50’ 12’’ E Altitude: 16 m a. s. l. Land use: Tundra Meteorological tower AWI NyÅlesund (MT): Coordinates: 078° 55’ 04’’ N, 011° 55’ 26’’ E Altitude: 14 m a. s. l. Land use: Tundra BSRN AWI Ny-Ålesund (BSRN): Coordinates: 078° 56’ 05’’ N, 011° 56’ E Altitude: 11 m a. s. l. Land use: Tundra Time zone Central European Time: CET = GMT + 1 h (winter) CEST = GMT + 2 h (summer). Given times and filenames reflect starting time of intervals UBT = University of Bayreuth; AWI = Alfred Wegener Institute for Polarand Marine Research; BSRN = Baseline Surface Radiation Network 7 2.2 Surface and weather conditions Table 2.1 lists the weather conditions during the ARCTEX-2009 campaign. There was midnight sun during the whole campaign. The surface conditions were constant (except the short precipitation events listed below). Table 2.1: Weather conditions during the ARCTEX-2009 campaign, time is CEST. August 12 overcast, predominantly light air, partly light breeze, temperature range: +4.2 °C to +6.8 °C August 13 predominantly overcast, partly light breeze during the day, drizzle at 9 p.m., temperature range: +3.7 °C to +7.2 °C August 14 predominantly overcast in the morning, later partly cloudy (midday till afternoon), windy from 9 a.m. to 10 p.m. ( 5 to 6 m s1), temperature range: +3.1 °C to +6.2 °C August 15 overcast, partly windy up to gentle breezes, temperature range: +1.7 °C to +3.5 °C August 16 fog in the morning hours and overcast until midday, later predominantly sunshine and partly cloudy (high clouds), predominantly calm, partly light breezes, temperature range: 0.7 °C to +5.0 °C August 17 sunshine until afternoon, later few high clouds and increasing wind, from 5 p.m. strong wind (7 to 8 m s1), temperature range: +0.9 °C to +7.5 °C August 18 strong Foehn wind (8 to 10 m s1) until afternoon, drizzle at 4 p.m. (app. 15min), light rain at 5:15 p.m. and 6:30 p.m. (app. 15min), later predominantly overcast, temperature range: +2.6 °C to +8.5 °C August 19 predominantly cloudy until midday, later overcast, windy until 13 a.m., later light breeze, temperature range: +3.9 °C to +7.1 °C 3 Overview of measurement sites The satellite image below (Figure 3.1) gives an overview of the Bayelva catchment including the installed instrument sites. It is located about 3 km west of the village of Ny-Ålesund. Figure 3.1: Crop of a high resolution satellite image of the Bayelva catchment with the installed measurement sites (EF = Bayelva Eddy-flux complex, BMT = Bayelva Meteorological tower, BPS = Bayelva Permafrost Station, SLSdry = Scintillometer UBT01 dry Tundra, SLSwet = Scintillometer UBT02 wet Tundra). The original image was processed by Ernst Hauber from the DLR (High Resolution Stereo Camera HRSC-AX; Resolution: 20 cm/pixel; Projection: UTM (WGS44); central meridian: 15 degree), ARCTEX-2009 campaign. 8 3.1.1 Meteorological tower AWI Ny-Ålesund (MT) The permanent, 10 m tall meteorological tower (MT) of the AWI (Figure 3.2) is located about 100 m south-east of the Building of the atmospheric observatory (AWI-OBS) and south of the village of Ny-Ålesund in the protected monitoring instrument area (about 5 m next to the driveway towards the Corbel-Station). The measurements of this station are part of the routine meteorological observation program (surface radiation and mast measurements) operating since 1994 and headed by the AWI. (http://www.awi-potsdam.de/MET/NyAlesund/wettertab.html). Figure 3.2: Ten meter tall meteorological tower (MT) of the Alfred Wegener Institute south of the AWI Scientific Observatory. Routine meteorological measurements AWI/IPEV station Ny-Ålesund (Svalbard), ARCTEX-2009 campaign. 9 6 Visualization of standard meteorological measurements 6.1 Synoptic situation Synoptic weather charts (mean sea level pressure analysis = MSLP) were provided by the UK Meteorological Office (UKMO), showing the isobars including fronts and troughs. The following charts outline the synoptic situation between August 12 and August 19, 2009, at 00 UTC, 06UTC, 12 UTC and 18 UTC. The chart of August 17, 2009, 12 UTC is missing. 16 17 18 19 20 21 22 23 24 25 Figure 6.2 Air temperature between August 12 and August 20, 2009. Blue line: air temperature in °C at 2 m a. g. l., red line: air temperature in °C at 10 m a. g. l. (both Bayelva meteorological tower BMT, Alfred Wegener Institute for Polar and Marine Research). Bayelva (Svalbard), ARCTEX-2009 campaign. Figure 6.3: Vertical difference of air temperature between August 12 and August 20, 2009. Blue dots: T difference of air temperature in K between 10 m and 2 m a. g. l (Bayelva meteorological tower BMT, Alfred Wegener Institute for Polar and Marine Research). Bayelva (Svalbard), ARCTEX-2009 campaign. 32 Humidity The observed relative air humidity (Figure 6.4) did not show much variation between August 12 and August 20. During Aug. 17 the level drops slightly from 90 to 80% to 70 to 60% caused by offshore advection of dry air mass from the east (inland). Figure 6.4: Humidity between August 12 and August 20, 2009. Blue line: relative humidity in % at 2 m a. g. l. (Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research). Bayelva (Svalbard), ARCTEX-2009 campaign. Wind speed and wind direction The horizontal wind speed at different heights above ground level (2 m and 10 m) was obtained by the routine observation of the meteorological tower (MT) at Ny-Ålesund of the Alfred Wegener Institute for Polar and Marine Research (Figure 6.5). A second wind speed and wind direction measurement at 2 m a. g. l. was retrieved from the Bayelva permafrost station of the AWI (BPS) in the Bayelva catchment itself (Fig. 6.6). Figure 6.5: Wind speed between August 12 and August 20, 2009. Blue dots: wind speed in m s1 at 2 m a. g. l., red dots: wind speed in m s1 at 10 m a. g. l. (both meteorological tower MT, Alfred Wegener Institute for Polar and Marine Research). Ny-Ålesund (Svalbard), ARCTEX-2009 campaign. 33 Figure 6.6: Wind speed and wind direction between August 12 and August 20, 2009. Blue line: wind speed in m s1 at 2 m a. g. l., red dots: wind direction in degree at 2 m a. g. l. (both Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research). Bayelva (Svalbard), ARCTEX2009 campaign. The wind direction (at 2 m and 10 m a. g. l.) was obtained by the meteorological routine observation of the 10 m tall meteorological tower (MT) at Ny-Ålesund and directly at Bayelva by the eddy-flux complex EF (at 2.90 m a. g. l.) of the Alfred Wegener Institute for Polar and Marine Research. The used wind sensor from the MT is a combined cup-anemometer and wind vane (Thies Clima, Germany), the EF-Station used the Ultrasonic CSAT3 anemometer. The Figure 6.7 shows the main wind direction sectors at Ny-Ålesund and at the Bayelva catchment during the ARCTEX-2009 campaign. This pattern of either south-easterly or easterly directions (more or less canalized air flow up and down the Kongsfjord and the glaciers) is typical most of the time during the year. The eddy-flux complex in the Bayelva catchment measured a southern to south-eastern component which could be an air flow from the glacier located in the south of the measurement site. 34 35 Figure 6.7: Frequency distribution of wind direction separated in 12 wind sectors and classified in 4 wind speed classes, August 12 to August 19, 2009. Top: distribution of the wind directions in degree measured at 2 m height a. g. l. Middle: distribution of the wind direction in degree measured at 10 m a. g. l. (both AWI meteorological tower (MT)). Bottom: distribution of the wind directions in degree measured at 2.90 m height a. g. l. (Bayelva eddy-flux complex AWI (EF)). Ny-Ålesund and Bayelva (Svalbard), ARCTEX-2009 campaign. 36 Radiation The main radiation measurements (1 min sampling) took place at the routine BSRN station of the AWI in Ny-Ålesund (Figure 6.8). An additional measurement (30 min sampling) took place at the Bayelva permafrost station BPS of the AWI (Figures 6.9 to 6.12), 3 km west of Ny-Ålesund, close to the Eddy-flux complex EF and the both University of Bayreuth Scintillometer pathways. Figure 6.8: Shortwave radiation between August 12 and August 20, 2009. Red dots: global radiation in W m2 measured with a CM11 (Kipp & Zonen) pyranometer (BSRN station, Alfred Wegener Institute for Polar and Marine Research). Ny-Ålesund (Svalbard), ARCTEX-2009 campaign. Figure 6.9: Shortwave radiation between August 12 and August 20, 2009. Blue line: global radiation in W m2 measured with a NR01 (Hukseflux) (Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research). Bayelva (Svalbard), ARCTEX-2009 campaign. 37 Figure 6.10: Ratio of reflected to global shortwave radiation (albedo) measured with a NR01 (Hukseflux) (Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research), August 12 to August 20, 2009. The Blue dots are showing the variance of the Albedo due to different elevation angles of the sun and due to different fraction of the half space from witch diffuse sky radiation or the - from the surface - reflected radiation can reach the sensors. Bayelva (Svalbard), ARCTEX-2009 campaign. Figure 6.11: Longwave radiation measured with a NR01 (Hukseflux) (Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research), August 12 to August 20, 2009. Red dots: incoming longwave radiation in W m2. Blue dots: emitted longwave radiation in W m2. Bayelva (Svalbard), ARCTEX-2009 campaign. 38 Figure 6.12: Surface radiation balance: radiation was measured with a NR01 (Hukseflux) (Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research), August 12 to August 20, 2009. Constituted by the micrometeorological convention, downward directed fluxes (global shortwave and incoming longwave radiation) are negative and upward directed fluxes (reflected shortwave and emitted longwave radiation) are positive. Bayelva (Svalbard), ARCTEX2009 campaign. Cloud Base height in meter For cloud base height measurements a laser (LIDAR) based ceilograph LD-40 is used since 1998 with a ceiling range between 23 m and 12 650 m height and with a measuring deviation of ±23 m (at solid objects). The ceilometer is part of the BSRN measuring field at Ny-Ålesund operated by the Alfred Wegener Institute. Figure 6.13: Cloud base height (cbh) in meter above ground between August 12 and August 20, 2009. Laser (LIDAR) based ceilograph measurements of the BSRN (Baseline Surface Radiation Network) station Ny-Ålesund operated by the Alfred Wegener Institute. Ny-Ålesund (Svalbard), ARCTEX-2009 campaign. 39 Accumulated precipitation in mm For precipitation measurements a tipping bucket rain gauge 52203 (RM Young) is used and is installed in the Bayelva catchment since 1998. Figure 6.14 shows no measurable precipitation in the time from August 12 to August 20 when the ACRTEX-2009 campaign took place. Nevertheless we noticed some drizzle on August 13 and August 18. Figure 6.14: Accumulated precipitation from August 1 to August 31, 2009. The measurement based on 60 minute summed up measurements of the BPS (Bayelva permafrost station BPS, Alfred Wegener Institute for Polar and Marine Research). Bayelva (Svalbard), ARCTEX-2009 campaign. 40 6.3 Daily charts Air temperature During the ARCTEX-2009 campaign air temperature was recorded by different instruments in the Bayelva catchment and different heights above ground using ventilated and radiationshielded thermometers (BPS and MT), a CSAT3 from the eddy-flux complex (EF) to obtain the sonic temperature, as well as a soil temperature probe (4.5 cm depth) at the Bayelva Permafrost station (BPS). The heights are given in each figure. A sampling integral of 30 minutes was used at the Bayelva stations (BPS, EF) and of 1 minute at the Ny-Ålesund site (MT). 41 48 49 50 Shortwave radiation and cloud base height The recordings of solar radiation and cloud base height were obtained from the international standardized radiation measurements of the Baseline Surface Radiation Network (BSRN), the laser ceilometer (cloud base height) and the Bayelva Permafrost station (BPS), all maintained by the Alfred Wegener Institute for Polar and Marine Research. The figures show the global (incoming) and reflected (outgoing) parts of the shortwave spectral range and the according cloud height. 51 52 53 Longwave radiation and cloud base height The recordings of the terrestrial radiation and the cloud base height were obtained from the international standardized radiation measurements of the Baseline Surface Radiation Network (BSRN), the laser ceilometer (cloud base height) and the Bayelva Permafrost station (BPS), all maintained by the Alfred Wegener Institute for Polar and Marine Research. The figures show the incoming and outgoing fluxes in the longwave spectral range and the corresponding cloud height. 54 55 56 57 7 Visualization of directly measured turbulence fluxes 7.1 Calculation of turbulent fluxes with the software package TK21 The turbulent fluxes were preand post-processed with the internationally standardized QA/QC software package TK21, developed by the Department of Micrometeorology, University of Bayreuth (Mauder and Foken, 2004; Mauder et al., 2008). The software package TK21 is based on 15 years of experiences. It was developed to calculate turbulent fluxes automatically for several international micrometeorological experiments since 1989. TK21 is capable of performing all of the post processing of turbulence measurements producing quality assured turbulent fluxes for a station automatically in one single run. It includes all corrections and tests, which are state of science (i.e. detection of spikes, application of Planar Fit method for coordinate transformation, determination of the time delay between sensors) and a quality assessment. The latter following a procedure proposed by Foken and Wichura (1996) and further developed by Foken et al. (2004). Two quality tests were applied to the flux data. The Steady State test is designed to detect non steady state conditions, which are an assumption of the eddy covariance method. This test compares a 30-minute covariance with the arithmetic mean of the six 5-minute covariances in this 30-minute interval. The agreement between both values is a measure of steady state conditions. The second test is based on the flux-variance similarity, which means that the ratio of the standard deviation of a turbulent parameter and its turbulent flux is nearly constant or a function, e.g. of the stability. These normalized standard deviations are called Integral Turbulence Characteristics (ITC). This test compares measured integral turbulence characteristics with modeled ones. The agreement between both values is a measure of well-developed turbulence. Foken, T; Göckede, M; Mauder, M; Mahrt, L; Amiro, BD; Munger, JW (2004): Post-field data quality control. in Lee X., Massman W, Law B : Handbook of Micrometeorology: A Guide for Surface Flux Measurement and Analysis, Kluwer, Dordrecht, 181-208. Foken, T; Wichura, B (1996): Tools for quality assessment of surface-based flux measurements. Agric Forest Meteorology, 78, 83-105. Mauder, M; Foken, T (2004): Documentation and Instruction Manual of the Eddy Covariance Software Package TK2. Work report University of Bayreuth, Dept of Micrometeorology, 26, ISSN 1614-8916. Mauder, M; Foken, T; Clement, R; Elbers, JA; Eugster, W; Grünwald, T; Heusinkveld, B; Kolle, O (2008): Quality control of CarboEurope flux data – Part 2: Inter-comparison of eddy-covariance software, Biogeosciences, 5, 451-462. Figure 7.9: Top: 5 min averaged values. Bottom: 30 min averaged values. Sensible heat flux QH at 2.9 m a. g. (grey line) obtained by the eddy-flux complex EF and the related quality flags of the Steady State test (Foken & Wichura, 1996; TK21-software) of the covariance of the fluctuations of the sonic temperature (Ts′) and vertical (w′) wind component (statflag_wTs). The classes 1 to 3 are good quality, the classes 4 to 6 are usable quality, class 7 and 8 are only for orientation, 9 has to be neglected, August 12 to August 20, 2009. Bayelva (Svalbard), ARCTEX-2009 campaign. 64 Figure 7.10: Top: 5 min averaged values. Bottom: 30 min averaged values. Sensible heat flux QH at 2.90 m a. g. (grey line) obtained by the eddy-flux complex EF and the related quality flags of the Integral Turbulence Characteristic test (ITC-test, Foken & Wichura, 1996; TK21-software) of the standard deviation (Ts) normalized by its dynamical parameter T (itcflag_Ts). The classes 1 to 3 are good quality, the classes 4 to 6 are usable quality, class 7 and 8 are only for orientation, 9 has to be neglected, August 12 to August 20, 2009. Bayelva (Svalbard), ARCTEX-2009 campaign. 65 Figure 7.11: Quality control using the quality flag system after Foken & Wichura (1996) by applying the TK21-software. Top: 5 min averaged values. Bottom: 30 min averaged values. Left: Steady State test of the covariance of the fluctuations of a) the horizontal wind components (u′, v′) and b) the sonic temperature (Ts′) and the vertical (w′) wind component (statflag_ustar and statflag_wTs). Right: Integral Turbulence Characteristic test (ITC-test) of the standard deviations (w and Ts) normalized by their dynamical parameters u and T (itcflag_w and itcflag_Ts). The classes 1 to 3 are good quality, the classes 4 to 6 are usable quality, class 7 and 8 are only for orientation, 9 has to be neglected, August 12 to August 20, 2009. Bayelva (Svalbard), ARCTEX-2009 campaign. 66 Figure 7.12: Quality control of the turbulent fluxes obtained by the eddy-flux complex EF applying the Planar Fit coordinate rotation method after Wilczak et al. (2001) ideally resulting in a w-value of zero averaged across the full data set August 12 to August 20, 2009. The plots show the correction effect (left with unrotated, right with rotated coordinate matrix) regarding the vertical wind component w in relation to the according wind direction (top) and regarding the vertical wind component w in relation to the according horizontal wind speed vh (bottom). Bayelva (Svalbard), ARCTEX-2009 campaign. 67 Figure 7.13: Top: 5 min averaged values. Bottom: 30 min averaged values. Sensible heat flux QH at 2.90 m a. g. (grey line) and the related atmospheric stability parameter  (z/L), whereas L is the Obukhov-length and z is the measurement height (2.90 m), both obtained by the eddy-flux complex EF. Bayelva (Svalbard), ARCTEX-2009 campaign. 68 Figure 7.14: Comparison of the sensible heat flux obtained by two independent measurement systems during August 12 to August 20, 2009, in the Bayelva catchment near Ny-Ålesund (Svalbard). The dark blue line (Qh EF) indicates the sensible heat flux QH and the brown line (Qe EF) indicates the latent heat flux QE at 2.90 m a. g. obtained by the eddy-flux complex EF using a Campbell CSAT3. The orange dots (Qh SLS dry) are indicating the sensible heat flux along a 100 m long laser scintillometer pathway (Scintec SLS 20) 1.21 m above dry ground near the fetch of the eddy-flux complex EF. The blue dots (Qh SLS wet) are indicating the sensible heat flux along a 100 m long laser scintillometer pathway (Scintec SLS 20) 1.22 m above wet ground near the fetch of the eddy-flux complex EF. For QH of the scintillometers the stability z/L was used to decide the appropriate flux directions. Bayelva (Svalbard), ARCTEX-2009 campaign. Figure 7.15: Recorded wind direction (red dots) and friction velocity u (blue line), and the related atmospheric stability parameter  (z/L, dark grey line, pos. values = stable, neg. values = unstable), whereas L is the Obukhov-length and z is the measurement height (2.90 m), all obtained by the eddy covariance complex EF, August 16 and August 17, 2009. Bayelva (Svalbard), ARCTEX-2009 campaign. 69 Figure 7.16: Recorded wind direction (red dots) and friction velocity u (blue line), and the related atmospheric stability parameter  (z/L, dark grey line, pos. values = stable, neg. values = unstable), whereas L is the Obukhov-length and z is the measurement height (2.90 m), all obtained by the eddy covariance complex EF, August 12 to August 20 2009. Bayelva (Svalbard), ARCTEX-2009 campaign. 70 7.3 Daily charts The figures in this chapter present the two independently measured sensible heat fluxes obtained from the eddy-flux complex EF and the laser scintillometer SLS during the ARCTEX-2009 campaign, August 12 to August 20. The graphs include information about a) the atmospheric stability parameter  (z/L), the sensible (Qh EF) and latent heat flux (Qe EF) all obtained by the eddy-flux complex (CSAT3, LI-7500) and b) the two laser-scintillometer section (Qh SLS wet tundra and Qh SLS dry tundra). For the analysis of the scintillometer measurements the stability z/L was used to decide the appropriate flux directions instead the usual vertical gradient of air temperature. All values are 5 minute averaged values. 71 72 73