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On December 6, 2019 at 11:28:14 PM UTC,
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Added resource associated report to St.Moritzersee_T-Mooring
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Added field
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to resource st.moritzlakeicewinter1617.zip in St.Moritzersee_T-Mooring
f | 1 | { | f | 1 | { |
2 | "author": "[\"Bouffard, Damien\"]", | 2 | "author": "[\"Bouffard, Damien\"]", | ||
3 | "author_email": null, | 3 | "author_email": null, | ||
4 | "creator_user_id": "064a4293-f097-4005-98d5-65b49b35ccf3", | 4 | "creator_user_id": "064a4293-f097-4005-98d5-65b49b35ccf3", | ||
5 | "extras": [ | 5 | "extras": [ | ||
6 | { | 6 | { | ||
7 | "key": "citation", | 7 | "key": "citation", | ||
8 | "value": "Bouffard, D. (2019). <i>St.Moritzersee_T-Mooring</i> | 8 | "value": "Bouffard, D. (2019). <i>St.Moritzersee_T-Mooring</i> | ||
9 | [Data set]. Eawag: Swiss Federal Institute of Aquatic Science and | 9 | [Data set]. Eawag: Swiss Federal Institute of Aquatic Science and | ||
10 | Technology. https://doi.org/10.25678/0000KK" | 10 | Technology. https://doi.org/10.25678/0000KK" | ||
11 | }, | 11 | }, | ||
12 | { | 12 | { | ||
13 | "key": "doi", | 13 | "key": "doi", | ||
14 | "value": "10.25678/0000kk" | 14 | "value": "10.25678/0000kk" | ||
15 | }, | 15 | }, | ||
16 | { | 16 | { | ||
17 | "key": "geographic_name", | 17 | "key": "geographic_name", | ||
18 | "value": "[\"St. Moritzersee\", \"Lej da San Murexxan\"]" | 18 | "value": "[\"St. Moritzersee\", \"Lej da San Murexxan\"]" | ||
19 | }, | 19 | }, | ||
20 | { | 20 | { | ||
21 | "key": "open_data", | 21 | "key": "open_data", | ||
22 | "value": "true" | 22 | "value": "true" | ||
23 | }, | 23 | }, | ||
24 | { | 24 | { | ||
25 | "key": "publicationlink", | 25 | "key": "publicationlink", | ||
26 | "value": "" | 26 | "value": "" | ||
27 | }, | 27 | }, | ||
28 | { | 28 | { | ||
29 | "key": "review_level", | 29 | "key": "review_level", | ||
30 | "value": "none" | 30 | "value": "none" | ||
31 | }, | 31 | }, | ||
32 | { | 32 | { | ||
33 | "key": "spatial", | 33 | "key": "spatial", | ||
34 | "value": "{ \"type\": \"Point\", \"coordinates\": [9.85238, | 34 | "value": "{ \"type\": \"Point\", \"coordinates\": [9.85238, | ||
35 | 46.49478] }" | 35 | 46.49478] }" | ||
36 | }, | 36 | }, | ||
37 | { | 37 | { | ||
38 | "key": "status", | 38 | "key": "status", | ||
39 | "value": "complete" | 39 | "value": "complete" | ||
40 | }, | 40 | }, | ||
41 | { | 41 | { | ||
42 | "key": "substances", | 42 | "key": "substances", | ||
43 | "value": "[]" | 43 | "value": "[]" | ||
44 | }, | 44 | }, | ||
45 | { | 45 | { | ||
46 | "key": "substances_generic", | 46 | "key": "substances_generic", | ||
47 | "value": "[]" | 47 | "value": "[]" | ||
48 | }, | 48 | }, | ||
49 | { | 49 | { | ||
50 | "key": "systems", | 50 | "key": "systems", | ||
51 | "value": "[\"Lake\"]" | 51 | "value": "[\"Lake\"]" | ||
52 | }, | 52 | }, | ||
53 | { | 53 | { | ||
54 | "key": "tags_string", | 54 | "key": "tags_string", | ||
55 | "value": "ice growing,inverse stratification,mooring" | 55 | "value": "ice growing,inverse stratification,mooring" | ||
56 | }, | 56 | }, | ||
57 | { | 57 | { | ||
58 | "key": "taxa", | 58 | "key": "taxa", | ||
59 | "value": "[]" | 59 | "value": "[]" | ||
60 | }, | 60 | }, | ||
61 | { | 61 | { | ||
62 | "key": "taxa_generic", | 62 | "key": "taxa_generic", | ||
63 | "value": "[]" | 63 | "value": "[]" | ||
64 | }, | 64 | }, | ||
65 | { | 65 | { | ||
66 | "key": "timerange", | 66 | "key": "timerange", | ||
67 | "value": "[\"[2016-10-26 TO 2017-06-17]\"]" | 67 | "value": "[\"[2016-10-26 TO 2017-06-17]\"]" | ||
68 | }, | 68 | }, | ||
69 | { | 69 | { | ||
70 | "key": "variables", | 70 | "key": "variables", | ||
71 | "value": "[\"pressure\", \"temperature\"]" | 71 | "value": "[\"pressure\", \"temperature\"]" | ||
72 | } | 72 | } | ||
73 | ], | 73 | ], | ||
74 | "groups": [ | 74 | "groups": [ | ||
75 | { | 75 | { | ||
76 | "description": "Various lake observables, including lake ice, | 76 | "description": "Various lake observables, including lake ice, | ||
77 | are related to climate and climate change and provide a good | 77 | are related to climate and climate change and provide a good | ||
78 | opportunity for long-term monitoring. Lakes (and as part of them lake | 78 | opportunity for long-term monitoring. Lakes (and as part of them lake | ||
79 | ice) is therefore considered an Essential Climate Variable (ECV) (WMO, | 79 | ice) is therefore considered an Essential Climate Variable (ECV) (WMO, | ||
80 | 2018) of the Global Climate Observing System (GCOS). In Switzerland, | 80 | 2018) of the Global Climate Observing System (GCOS). In Switzerland, | ||
81 | the implementation of GCOS is coordinated by the Swiss GCOS Office at | 81 | the implementation of GCOS is coordinated by the Swiss GCOS Office at | ||
82 | the Federal Office for Meteorology and Climatology MeteoSwiss. In 2007 | 82 | the Federal Office for Meteorology and Climatology MeteoSwiss. In 2007 | ||
83 | (updated in 2018), MeteoSwiss published the first national inventory | 83 | (updated in 2018), MeteoSwiss published the first national inventory | ||
84 | of the most important climate observations in Switzerland (MeteoSwiss, | 84 | of the most important climate observations in Switzerland (MeteoSwiss, | ||
85 | 2018). For each ECV, including observations of lake ice subsumed under | 85 | 2018). For each ECV, including observations of lake ice subsumed under | ||
86 | the ECV \u201cLakes\u201d, and international centre, the inventory | 86 | the ECV \u201cLakes\u201d, and international centre, the inventory | ||
87 | report identified possible gaps regarding the legal basis, definition | 87 | report identified possible gaps regarding the legal basis, definition | ||
88 | of responsibilities, and availability of financial resources for the | 88 | of responsibilities, and availability of financial resources for the | ||
89 | continuation of observations and operation, respectively. In 2008, | 89 | continuation of observations and operation, respectively. In 2008, | ||
90 | considering the findings of this report, the Federal Council approved | 90 | considering the findings of this report, the Federal Council approved | ||
91 | a financial contribution to secure the continuation of time series and | 91 | a financial contribution to secure the continuation of time series and | ||
92 | international centres at risk of discontinuation, as a long-term | 92 | international centres at risk of discontinuation, as a long-term | ||
93 | contribution to GCOS. Concerning the ECV \u201cLakes\u201d, in the | 93 | contribution to GCOS. Concerning the ECV \u201cLakes\u201d, in the | ||
94 | global National Snow and Ice Data Center (NSIDC), Boulder, Colorado | 94 | global National Snow and Ice Data Center (NSIDC), Boulder, Colorado | ||
95 | database on lake ice-on/off dates, currently only Lake St. Moritz is | 95 | database on lake ice-on/off dates, currently only Lake St. Moritz is | ||
96 | partly included (till 2012). Further, existing observations and data | 96 | partly included (till 2012). Further, existing observations and data | ||
97 | from local authorities and publications are not systematic and come | 97 | from local authorities and publications are not systematic and come | ||
98 | from different, uncoordinated and not secured sources. Traditionally, | 98 | from different, uncoordinated and not secured sources. Traditionally, | ||
99 | on-shore observers collected the information of lake ice recording the | 99 | on-shore observers collected the information of lake ice recording the | ||
100 | visible frozen-edge. Within the past two decades due to lack of budget | 100 | visible frozen-edge. Within the past two decades due to lack of budget | ||
101 | and/or human resources, the number of field observations declined and | 101 | and/or human resources, the number of field observations declined and | ||
102 | mostly totally stopped. At the same time, the potential of different | 102 | mostly totally stopped. At the same time, the potential of different | ||
103 | remote sensing sensors covering varying time periods and spatial | 103 | remote sensing sensors covering varying time periods and spatial | ||
104 | coverage to measure the occurrence of lake ice was demonstrated by | 104 | coverage to measure the occurrence of lake ice was demonstrated by | ||
105 | several investigations. Thus, following the need for an integrated | 105 | several investigations. Thus, following the need for an integrated | ||
106 | multi-temporal monitoring of lake ice in Switzerland, MeteoSwiss in | 106 | multi-temporal monitoring of lake ice in Switzerland, MeteoSwiss in | ||
107 | the framework of GCOS Switzerland supported this 2-year project to | 107 | the framework of GCOS Switzerland supported this 2-year project to | ||
108 | explore not only the use of satellite images but also the | 108 | explore not only the use of satellite images but also the | ||
109 | possibilities of Webcams and in-situ measurements.\r\nThe aim of this | 109 | possibilities of Webcams and in-situ measurements.\r\nThe aim of this | ||
110 | project is to monitor some target lakes and detect the extent of ice | 110 | project is to monitor some target lakes and detect the extent of ice | ||
111 | and especially the ice-on/off dates, with focus on the integration of | 111 | and especially the ice-on/off dates, with focus on the integration of | ||
112 | various input data and processing methods. Regarding ice-on/off dates, | 112 | various input data and processing methods. Regarding ice-on/off dates, | ||
113 | the GCOS requirements are daily observations and an accuracy of +/- 2 | 113 | the GCOS requirements are daily observations and an accuracy of +/- 2 | ||
114 | days. The target lakes were: St. Moritz, Silvaplana, Sils, Sihl, | 114 | days. The target lakes were: St. Moritz, Silvaplana, Sils, Sihl, | ||
115 | Greifen and Aegeri, whereby only the first four were mainly frozen | 115 | Greifen and Aegeri, whereby only the first four were mainly frozen | ||
116 | during the observation period and thus processed. These lakes have | 116 | during the observation period and thus processed. These lakes have | ||
117 | variable area (very small to middle-sized), altitude (low to high) and | 117 | variable area (very small to middle-sized), altitude (low to high) and | ||
118 | surrounding topography (flat/hilly to mountainous) and freeze | 118 | surrounding topography (flat/hilly to mountainous) and freeze | ||
119 | generally often, covering thus difficult to medium difficulty cases, | 119 | generally often, covering thus difficult to medium difficulty cases, | ||
120 | regarding area, altitude and topography. For all image data, only | 120 | regarding area, altitude and topography. For all image data, only | ||
121 | cloud-free pixels lying entirely within the lake were processed. The | 121 | cloud-free pixels lying entirely within the lake were processed. The | ||
122 | observation period was mainly the winter 2016-17. During the project, | 122 | observation period was mainly the winter 2016-17. During the project, | ||
123 | various approaches were developed, implemented, tested and compared. | 123 | various approaches were developed, implemented, tested and compared. | ||
124 | Firstly, low spatial resolution (250 - 1000 m) but high temporal | 124 | Firstly, low spatial resolution (250 - 1000 m) but high temporal | ||
125 | resolution (1 day) satellite images from the optical sensors MODIS and | 125 | resolution (1 day) satellite images from the optical sensors MODIS and | ||
126 | VIIRS were used. Secondly, and as a pilot project, the use of existing | 126 | VIIRS were used. Secondly, and as a pilot project, the use of existing | ||
127 | public Webcams was investigated for (a) validation of results from | 127 | public Webcams was investigated for (a) validation of results from | ||
128 | satellite data, and (b) independent estimation of lake ice, especially | 128 | satellite data, and (b) independent estimation of lake ice, especially | ||
129 | for small lakes like St. Moritz, that could not be possibly monitored | 129 | for small lakes like St. Moritz, that could not be possibly monitored | ||
130 | in the satellite images. Thirdly, in-situ measurements were made in | 130 | in the satellite images. Thirdly, in-situ measurements were made in | ||
131 | order to characterize the development of the temperature profiles and | 131 | order to characterize the development of the temperature profiles and | ||
132 | partly pressure before freezing and under the ice-cover until melting. | 132 | partly pressure before freezing and under the ice-cover until melting. | ||
133 | Besides the validation of the results from other data, this in-situ | 133 | Besides the validation of the results from other data, this in-situ | ||
134 | data is used to calibrate a one-dimensional physical lake model so | 134 | data is used to calibrate a one-dimensional physical lake model so | ||
135 | that the criteria for freezing of different Swiss lakes can be derived | 135 | that the criteria for freezing of different Swiss lakes can be derived | ||
136 | as a function of meteorological and morphometric conditions. It is | 136 | as a function of meteorological and morphometric conditions. It is | ||
137 | expected that the developed methods and software can be used, possibly | 137 | expected that the developed methods and software can be used, possibly | ||
138 | with some modifications, also for other data acquired for the same | 138 | with some modifications, also for other data acquired for the same | ||
139 | lakes or other ones in Switzerland and abroad. The project is a | 139 | lakes or other ones in Switzerland and abroad. The project is a | ||
140 | feasibility study, which should lead to a comparison and analysis of | 140 | feasibility study, which should lead to a comparison and analysis of | ||
141 | the above three techniques and recommendations to MeteoSwiss for | 141 | the above three techniques and recommendations to MeteoSwiss for | ||
142 | further actions. This report presents the results of the project | 142 | further actions. This report presents the results of the project | ||
143 | work.\r\nUsing MODIS and VIIRS satellite data, ETHZ proposed a | 143 | work.\r\nUsing MODIS and VIIRS satellite data, ETHZ proposed a | ||
144 | processing chain for lake ice monitoring. We tackled lake ice | 144 | processing chain for lake ice monitoring. We tackled lake ice | ||
145 | detection as a pixel-wise, two-class (frozen/non-frozen) semantic | 145 | detection as a pixel-wise, two-class (frozen/non-frozen) semantic | ||
146 | segmentation problem with Support Vector Machine (SVM) classification. | 146 | segmentation problem with Support Vector Machine (SVM) classification. | ||
147 | Four different lakes were analysed: Sihl, Sils, Silvaplana and St. | 147 | Four different lakes were analysed: Sihl, Sils, Silvaplana and St. | ||
148 | Moritz using both MODIS and VIIRS data. While we have concentrated on | 148 | Moritz using both MODIS and VIIRS data. While we have concentrated on | ||
149 | lakes in Switzerland, the ETHZ methodology is generic and the results | 149 | lakes in Switzerland, the ETHZ methodology is generic and the results | ||
150 | could hopefully be directly applied to other lakes with similar | 150 | could hopefully be directly applied to other lakes with similar | ||
151 | conditions, in Switzerland and abroad, and possibly to similar | 151 | conditions, in Switzerland and abroad, and possibly to similar | ||
152 | sensors. To assess the performance, the data from both MODIS and VIIRS | 152 | sensors. To assess the performance, the data from both MODIS and VIIRS | ||
153 | were processed from one full winter (2016/17) including the relatively | 153 | were processed from one full winter (2016/17) including the relatively | ||
154 | short but challenging freezing and melting periods, where frozen and | 154 | short but challenging freezing and melting periods, where frozen and | ||
155 | non-frozen pixels co-exist on the same lake. Using MODIS data, we also | 155 | non-frozen pixels co-exist on the same lake. Using MODIS data, we also | ||
156 | processed dates from 2011/12 and we demonstrate that the ETHZ approach | 156 | processed dates from 2011/12 and we demonstrate that the ETHZ approach | ||
157 | gives consistent results over multiple winters, and that it | 157 | gives consistent results over multiple winters, and that it | ||
158 | generalizes fairly well from one winter to another. For both MODIS and | 158 | generalizes fairly well from one winter to another. For both MODIS and | ||
159 | VIIRS, we have also shown that the model generalizes well across | 159 | VIIRS, we have also shown that the model generalizes well across | ||
160 | lakes.\r\nETHZ dealt with the feasibility of lake ice monitoring using | 160 | lakes.\r\nETHZ dealt with the feasibility of lake ice monitoring using | ||
161 | Webcam images as a supplement or alternative to other monitoring | 161 | Webcam images as a supplement or alternative to other monitoring | ||
162 | methods. Therefore, publically available Webcam images capturing six | 162 | methods. Therefore, publically available Webcam images capturing six | ||
163 | Swiss lakes were downloaded from the Internet in the periods of the | 163 | Swiss lakes were downloaded from the Internet in the periods of the | ||
164 | winters 2016/2017 and 2017/2018. Our evaluation was based on two | 164 | winters 2016/2017 and 2017/2018. Our evaluation was based on two | ||
165 | cameras (high- and low-resolution) monitoring the lake of St. Moritz. | 165 | cameras (high- and low-resolution) monitoring the lake of St. Moritz. | ||
166 | To predict the lake ice coverage of the observed water body, fully | 166 | To predict the lake ice coverage of the observed water body, fully | ||
167 | Connected Neuronal Networks (part of Deep Learning and Artificial | 167 | Connected Neuronal Networks (part of Deep Learning and Artificial | ||
168 | Intelligence methods) were utilized. Given an input image, such | 168 | Intelligence methods) were utilized. Given an input image, such | ||
169 | networks are designed to predict pixel-wise class probabilities. For | 169 | networks are designed to predict pixel-wise class probabilities. For | ||
170 | the problem at hand, the target classes were: snow, ice, water and | 170 | the problem at hand, the target classes were: snow, ice, water and | ||
171 | clutter. Several tests were conducted to identify important parameters | 171 | clutter. Several tests were conducted to identify important parameters | ||
172 | for the intensive training of such networks. Moreover, generalization | 172 | for the intensive training of such networks. Moreover, generalization | ||
173 | capabilities with respect to differing cameras and to data recorded in | 173 | capabilities with respect to differing cameras and to data recorded in | ||
174 | different winters were investigated. In contrast to optical satellite | 174 | different winters were investigated. In contrast to optical satellite | ||
175 | data, Webcams typically record multiple images per day. A median-based | 175 | data, Webcams typically record multiple images per day. A median-based | ||
176 | strategy to fuse such results to derive daily predictions was | 176 | strategy to fuse such results to derive daily predictions was | ||
177 | implemented. Moreover, possibilities of further exploiting temporal | 177 | implemented. Moreover, possibilities of further exploiting temporal | ||
178 | redundancy to improve predictions were explored by using two | 178 | redundancy to improve predictions were explored by using two | ||
179 | additional network architectures.\r\nThe Remote Sensing Research | 179 | additional network architectures.\r\nThe Remote Sensing Research | ||
180 | Group, Institute of Geography, University of Bern focuses on the | 180 | Group, Institute of Geography, University of Bern focuses on the | ||
181 | development of a physical approach to monitor lake ice based on data | 181 | development of a physical approach to monitor lake ice based on data | ||
182 | of the satellite sensor VIIRS (Visible Infrared Imaging Radiometer | 182 | of the satellite sensor VIIRS (Visible Infrared Imaging Radiometer | ||
183 | Suite) on-board of NOAA satellites Suomi-NPP. The advantage of the | 183 | Suite) on-board of NOAA satellites Suomi-NPP. The advantage of the | ||
184 | VIIRS data is the daily temporal resolution and improved spatial | 184 | VIIRS data is the daily temporal resolution and improved spatial | ||
185 | resolution of 375m considering the high-resolution channels | 185 | resolution of 375m considering the high-resolution channels | ||
186 | (I-channels). A comprehensive pre-processing chain has been developed | 186 | (I-channels). A comprehensive pre-processing chain has been developed | ||
187 | and implemented to efficiently obtain projected data of the region of | 187 | and implemented to efficiently obtain projected data of the region of | ||
188 | interests (target lakes in Switzerland) from multiple scans. Not only | 188 | interests (target lakes in Switzerland) from multiple scans. Not only | ||
189 | the scientific data records of VIIRS data (e.g., radiometric data, | 189 | the scientific data records of VIIRS data (e.g., radiometric data, | ||
190 | geolocation information) were processed but also environmental data | 190 | geolocation information) were processed but also environmental data | ||
191 | records (e.g., VIIRS M-band surface temperature), and intermediate | 191 | records (e.g., VIIRS M-band surface temperature), and intermediate | ||
192 | products (e.g., cloud masks), which were needed for product retrieval. | 192 | products (e.g., cloud masks), which were needed for product retrieval. | ||
193 | The developed approach considers surface temperature and reflectance | 193 | The developed approach considers surface temperature and reflectance | ||
194 | values in the visible and near-infrared spectra. The method relies on | 194 | values in the visible and near-infrared spectra. The method relies on | ||
195 | the assumption that a frozen water surface has a temperature below | 195 | the assumption that a frozen water surface has a temperature below | ||
196 | 0\u00b0C and an ice layer increases the reflectance in the | 196 | 0\u00b0C and an ice layer increases the reflectance in the | ||
197 | visible/near-infrared wavelengths. Retrieval of surface temperature | 197 | visible/near-infrared wavelengths. Retrieval of surface temperature | ||
198 | using only one channel in the atmospheric window requires a procedure | 198 | using only one channel in the atmospheric window requires a procedure | ||
199 | to correct for atmospheric effects (attenuation). Therefore, a single | 199 | to correct for atmospheric effects (attenuation). Therefore, a single | ||
200 | channel PMW (Physical Mono Window) model has been adapted to the | 200 | channel PMW (Physical Mono Window) model has been adapted to the | ||
201 | thermal I-band data of the VIIRS sensor (I05) considering atmospheric | 201 | thermal I-band data of the VIIRS sensor (I05) considering atmospheric | ||
202 | data from the European Center for Medium Weather Forecast (ECMWF), | 202 | data from the European Center for Medium Weather Forecast (ECMWF), | ||
203 | which were required for the radiative transfer modelling to minimize | 203 | which were required for the radiative transfer modelling to minimize | ||
204 | atmospheric attenuation. The accuracy of the retrieved VIIRS I-band | 204 | atmospheric attenuation. The accuracy of the retrieved VIIRS I-band | ||
205 | PMW Lake Surface Water Temperature (LSWT) has been assessed with | 205 | PMW Lake Surface Water Temperature (LSWT) has been assessed with | ||
206 | cross-satellite comparison and temperature based validation for Lake | 206 | cross-satellite comparison and temperature based validation for Lake | ||
207 | Geneva (station Buchillon) and the target lakes Lake Greifen and Lake | 207 | Geneva (station Buchillon) and the target lakes Lake Greifen and Lake | ||
208 | Sils.\r\nThe assessment of thermal infrared-derived surface | 208 | Sils.\r\nThe assessment of thermal infrared-derived surface | ||
209 | temperatures indicates an overall good performance of the physical | 209 | temperatures indicates an overall good performance of the physical | ||
210 | mono window LSWT retrieval method for VIIRS I-band data. Therefore, | 210 | mono window LSWT retrieval method for VIIRS I-band data. Therefore, | ||
211 | lake ice detection, based on LSWT, the normalized difference snow | 211 | lake ice detection, based on LSWT, the normalized difference snow | ||
212 | index (NDSI) and additional thresholds have been accomplished for the | 212 | index (NDSI) and additional thresholds have been accomplished for the | ||
213 | two target lakes for October 2016 to April 2017. Considering both the | 213 | two target lakes for October 2016 to April 2017. Considering both the | ||
214 | VIIRS I-band reflectance and thermal infrared-derived LSWT were a | 214 | VIIRS I-band reflectance and thermal infrared-derived LSWT were a | ||
215 | satisfying approach for lake ice detection, even for small lakes (e.g. | 215 | satisfying approach for lake ice detection, even for small lakes (e.g. | ||
216 | Lake Sils). The implemented two-step-approach used these results to | 216 | Lake Sils). The implemented two-step-approach used these results to | ||
217 | determine, without user-interaction, the thresholds to retrieve ice | 217 | determine, without user-interaction, the thresholds to retrieve ice | ||
218 | phenology. Finally, this results in an automatic determination of | 218 | phenology. Finally, this results in an automatic determination of | ||
219 | duration of ice cover (phenology) due to the identification of | 219 | duration of ice cover (phenology) due to the identification of | ||
220 | first/last day with ice cover, even for small lakes where only | 220 | first/last day with ice cover, even for small lakes where only | ||
221 | four-six 375m-pixels being not affected by the shoreline. Hence, the | 221 | four-six 375m-pixels being not affected by the shoreline. Hence, the | ||
222 | developments made for this feasibility study were successful and the | 222 | developments made for this feasibility study were successful and the | ||
223 | pre-operational concept of our modular procedure can be part of an | 223 | pre-operational concept of our modular procedure can be part of an | ||
224 | operational service.\r\nIn-situ measurements and processing were | 224 | operational service.\r\nIn-situ measurements and processing were | ||
225 | performed by EAWAG. There is no direct method to measure ice coverage | 225 | performed by EAWAG. There is no direct method to measure ice coverage | ||
226 | in lakes. Time series of lake temperatures are often used to assess | 226 | in lakes. Time series of lake temperatures are often used to assess | ||
227 | freezing and melting conditions. Yet, the 0\u00b0C boundary condition | 227 | freezing and melting conditions. Yet, the 0\u00b0C boundary condition | ||
228 | for ice cover in lakes is limited to a very thin layer at the surface | 228 | for ice cover in lakes is limited to a very thin layer at the surface | ||
229 | (0 cm) immediately under the ice and is practically nearly impossible | 229 | (0 cm) immediately under the ice and is practically nearly impossible | ||
230 | to measure with moorings. In this project, we tested different | 230 | to measure with moorings. In this project, we tested different | ||
231 | approaches to monitor the ice cover period by analysing the changes in | 231 | approaches to monitor the ice cover period by analysing the changes in | ||
232 | lake dynamics during ice-free and ice covered period. Namely, we | 232 | lake dynamics during ice-free and ice covered period. Namely, we | ||
233 | observed that (i) the correlation in the temperature time series of | 233 | observed that (i) the correlation in the temperature time series of | ||
234 | two closely vertically located sensors changed when the external | 234 | two closely vertically located sensors changed when the external | ||
235 | forcing are modified by the ice. Similar results can be observed | 235 | forcing are modified by the ice. Similar results can be observed | ||
236 | through (ii) wavelet and Fourier analysis of the temporal evolution of | 236 | through (ii) wavelet and Fourier analysis of the temporal evolution of | ||
237 | a single temperature logger with a noticeable drop in the energy (e.g. | 237 | a single temperature logger with a noticeable drop in the energy (e.g. | ||
238 | temperature fluctuations) during the ice covered period. Lastly, | 238 | temperature fluctuations) during the ice covered period. Lastly, | ||
239 | (iii), we evaluated the potential of using a high frequency pressure | 239 | (iii), we evaluated the potential of using a high frequency pressure | ||
240 | sensor to track the ice-on/off periods. Finally, the ice phenology was | 240 | sensor to track the ice-on/off periods. Finally, the ice phenology was | ||
241 | investigated with two different numerical models. A fully | 241 | investigated with two different numerical models. A fully | ||
242 | deterministic hydrodynamic model (simstrat.eawag.ch) provided | 242 | deterministic hydrodynamic model (simstrat.eawag.ch) provided | ||
243 | information related to the sensitivity of the ice coverage to the | 243 | information related to the sensitivity of the ice coverage to the | ||
244 | meteorological forcing (e.g. mostly wind and air temperature) and lake | 244 | meteorological forcing (e.g. mostly wind and air temperature) and lake | ||
245 | characteristics (e.g. bathymetry). This model together with a second | 245 | characteristics (e.g. bathymetry). This model together with a second | ||
246 | hybrid model were used to evaluate the long term phenology of frozen | 246 | hybrid model were used to evaluate the long term phenology of frozen | ||
247 | lakes and will allow estimate of the change in phenology under climate | 247 | lakes and will allow estimate of the change in phenology under climate | ||
248 | change conditions (with CH2018 dataset).\r\nThe results of ice-on/off | 248 | change conditions (with CH2018 dataset).\r\nThe results of ice-on/off | ||
249 | dates were based on ground-truth, mainly consisting of visual | 249 | dates were based on ground-truth, mainly consisting of visual | ||
250 | interpretation of Webcam images, which had some deficiencies and | 250 | interpretation of Webcam images, which had some deficiencies and | ||
251 | cannot be fully trusted. Furthermore, for the satellite data, clouds | 251 | cannot be fully trusted. Furthermore, for the satellite data, clouds | ||
252 | on and/or close to the ice-on/off dates led in some cases to large | 252 | on and/or close to the ice-on/off dates led in some cases to large | ||
253 | errors in the determination of these dates. The comparison of the | 253 | errors in the determination of these dates. The comparison of the | ||
254 | different monitoring methods was not based on sufficiently extensive | 254 | different monitoring methods was not based on sufficiently extensive | ||
255 | and timely co-incident data. In spite of these difficulties, some very | 255 | and timely co-incident data. In spite of these difficulties, some very | ||
256 | valuable conclusions can still be drawn. Small lakes (< 2 km2) are | 256 | valuable conclusions can still be drawn. Small lakes (< 2 km2) are | ||
257 | problematic for satellite images with a ground pixel size of about | 257 | problematic for satellite images with a ground pixel size of about | ||
258 | 250-400m and more. Webcams (though in this case with limited tests) | 258 | 250-400m and more. Webcams (though in this case with limited tests) | ||
259 | and in-situ (temperature-based) measurements showed the best accuracy. | 259 | and in-situ (temperature-based) measurements showed the best accuracy. | ||
260 | Optical satellite data suffer from clouds, cloud mask errors, | 260 | Optical satellite data suffer from clouds, cloud mask errors, | ||
261 | reflectance variations and other factors, and their accuracy regarding | 261 | reflectance variations and other factors, and their accuracy regarding | ||
262 | ice-on/off was worse. The two different processing methods (ETHZ and | 262 | ice-on/off was worse. The two different processing methods (ETHZ and | ||
263 | UniBe) of the same VIIRS data had generally similar performance but | 263 | UniBe) of the same VIIRS data had generally similar performance but | ||
264 | differences should be investigated. The main problem for all data | 264 | differences should be investigated. The main problem for all data | ||
265 | (apart in-situ) is the separation between transparent/clear ice | 265 | (apart in-situ) is the separation between transparent/clear ice | ||
266 | (usually thin) and water, particularly in the freeze-up (but also less | 266 | (usually thin) and water, particularly in the freeze-up (but also less | ||
267 | in the break-up) period, because of very similar reflectance. This | 267 | in the break-up) period, because of very similar reflectance. This | ||
268 | problem gets worse with reduced spatial resolution of the images. Even | 268 | problem gets worse with reduced spatial resolution of the images. Even | ||
269 | careful visual interpretation of image data cannot reliably | 269 | careful visual interpretation of image data cannot reliably | ||
270 | distinguish between these two cases. Unfortunately, the critical | 270 | distinguish between these two cases. Unfortunately, the critical | ||
271 | ice-on/off dates involve water and ice (snow usually comes later on | 271 | ice-on/off dates involve water and ice (snow usually comes later on | ||
272 | ice-on and melts earlier than ice-off) and thus, accurate | 272 | ice-on and melts earlier than ice-off) and thus, accurate | ||
273 | identification of transparent ice or water is crucial for the accurate | 273 | identification of transparent ice or water is crucial for the accurate | ||
274 | identification of ice-on/off dates.\r\nWhile as known, satellite data | 274 | identification of ice-on/off dates.\r\nWhile as known, satellite data | ||
275 | is the best operational input for global coverage, but partly also in | 275 | is the best operational input for global coverage, but partly also in | ||
276 | Switzerland, for Switzerland Webcam and in-situ data are very | 276 | Switzerland, for Switzerland Webcam and in-situ data are very | ||
277 | valuable. Further data, than those used in this project, should | 277 | valuable. Further data, than those used in this project, should | ||
278 | include radar satellite data (as highest priority to avoid the cloud | 278 | include radar satellite data (as highest priority to avoid the cloud | ||
279 | problem) and additionally optical high spatial resolution satellite | 279 | problem) and additionally optical high spatial resolution satellite | ||
280 | data (especially the free ESA Sentinel-1/2 data), better Webcams | 280 | data (especially the free ESA Sentinel-1/2 data), better Webcams | ||
281 | (especially with Pan-Tilt-Zoom) and extended in-situ measurements (in | 281 | (especially with Pan-Tilt-Zoom) and extended in-situ measurements (in | ||
282 | combination with local, cheap meteo stations and better Webcams). For | 282 | combination with local, cheap meteo stations and better Webcams). For | ||
283 | in-situ observations and generally, cooperation with Swiss Federal and | 283 | in-situ observations and generally, cooperation with Swiss Federal and | ||
284 | other agencies and stakeholders would be very beneficial.", | 284 | other agencies and stakeholders would be very beneficial.", | ||
285 | "display_name": "Integrated monitoring of icing-up of selected | 285 | "display_name": "Integrated monitoring of icing-up of selected | ||
286 | swiss lakes", | 286 | swiss lakes", | ||
287 | "id": "8668c43f-db0f-4e25-b915-a910cde0ac4e", | 287 | "id": "8668c43f-db0f-4e25-b915-a910cde0ac4e", | ||
288 | "image_display_url": | 288 | "image_display_url": | ||
289 | st:5000/uploads/group/2016-12-05-092326.70809515-71StMoritzersee.jpg", | 289 | st:5000/uploads/group/2016-12-05-092326.70809515-71StMoritzersee.jpg", | ||
290 | "name": | 290 | "name": | ||
291 | "integrated-monitoring-of-icing-up-of-selected-swiss-lakes", | 291 | "integrated-monitoring-of-icing-up-of-selected-swiss-lakes", | ||
292 | "title": "Integrated monitoring of icing-up of selected swiss | 292 | "title": "Integrated monitoring of icing-up of selected swiss | ||
293 | lakes" | 293 | lakes" | ||
294 | } | 294 | } | ||
295 | ], | 295 | ], | ||
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298 | "license_id": null, | 298 | "license_id": null, | ||
299 | "license_title": null, | 299 | "license_title": null, | ||
300 | "maintainer": "Pluess, Michael", | 300 | "maintainer": "Pluess, Michael", | ||
301 | "maintainer_email": "michael.pluess@eawag.ch", | 301 | "maintainer_email": "michael.pluess@eawag.ch", | ||
302 | "metadata_created": "2019-12-06T23:27:48.989352", | 302 | "metadata_created": "2019-12-06T23:27:48.989352", | ||
303 | "metadata_modified": "2019-12-06T23:27:48.989358", | 303 | "metadata_modified": "2019-12-06T23:27:48.989358", | ||
304 | "name": "st-moritz-t-mooring", | 304 | "name": "st-moritz-t-mooring", | ||
305 | "notes": "Mooring with temperature and pressure loggers on lake | 305 | "notes": "Mooring with temperature and pressure loggers on lake | ||
306 | St.Moritz to observe ice growing and inverse stratification", | 306 | St.Moritz to observe ice growing and inverse stratification", | ||
n | 307 | "num_resources": 1, | n | 307 | "num_resources": 2, |
308 | "num_tags": 3, | 308 | "num_tags": 3, | ||
309 | "organization": { | 309 | "organization": { | ||
310 | "approval_status": "approved", | 310 | "approval_status": "approved", | ||
311 | "created": "2019-09-18T14:11:50.244436", | 311 | "created": "2019-09-18T14:11:50.244436", | ||
312 | "description": "The Aquatic Physics Group studies physical | 312 | "description": "The Aquatic Physics Group studies physical | ||
313 | processes mainly in lakes, reservoirs and rivers. We have two | 313 | processes mainly in lakes, reservoirs and rivers. We have two | ||
314 | approaches:\r\n\r\n+ From small scale in situ turbulence measurements | 314 | approaches:\r\n\r\n+ From small scale in situ turbulence measurements | ||
315 | to large scale three-dimensional models.\r\n\r\n+ Aquatic physics as a | 315 | to large scale three-dimensional models.\r\n\r\n+ Aquatic physics as a | ||
316 | tool to understand aquatic systems.\r\n\r\nOur research consists in | 316 | tool to understand aquatic systems.\r\n\r\nOur research consists in | ||
317 | dedicated in-situ measurements together with large scale three | 317 | dedicated in-situ measurements together with large scale three | ||
318 | dimensional numerical models. This approach is perfectly fitted to | 318 | dimensional numerical models. This approach is perfectly fitted to | ||
319 | understand the spatial variability of lakes.", | 319 | understand the spatial variability of lakes.", | ||
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324 | "name": "aquatic-physics", | 324 | "name": "aquatic-physics", | ||
325 | "state": "active", | 325 | "state": "active", | ||
326 | "title": "Aquatic Physics", | 326 | "title": "Aquatic Physics", | ||
327 | "type": "organization" | 327 | "type": "organization" | ||
328 | }, | 328 | }, | ||
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359 | } | 383 | } | ||
360 | ], | 384 | ], | ||
361 | "state": "active", | 385 | "state": "active", | ||
362 | "tags": [ | 386 | "tags": [ | ||
363 | { | 387 | { | ||
364 | "display_name": "ice growing", | 388 | "display_name": "ice growing", | ||
365 | "id": "a3a8232c-fb12-448b-a8b2-748c7919661f", | 389 | "id": "a3a8232c-fb12-448b-a8b2-748c7919661f", | ||
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367 | "state": "active", | 391 | "state": "active", | ||
368 | "vocabulary_id": null | 392 | "vocabulary_id": null | ||
369 | }, | 393 | }, | ||
370 | { | 394 | { | ||
371 | "display_name": "inverse stratification", | 395 | "display_name": "inverse stratification", | ||
372 | "id": "469e922e-947c-4971-9f2f-88adeea2dcff", | 396 | "id": "469e922e-947c-4971-9f2f-88adeea2dcff", | ||
373 | "name": "inverse stratification", | 397 | "name": "inverse stratification", | ||
374 | "state": "active", | 398 | "state": "active", | ||
375 | "vocabulary_id": null | 399 | "vocabulary_id": null | ||
376 | }, | 400 | }, | ||
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379 | "id": "bbac2764-c4e8-4278-96d3-b8778e5717e7", | 403 | "id": "bbac2764-c4e8-4278-96d3-b8778e5717e7", | ||
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382 | "vocabulary_id": null | 406 | "vocabulary_id": null | ||
383 | } | 407 | } | ||
384 | ], | 408 | ], | ||
385 | "title": "St.Moritzersee_T-Mooring", | 409 | "title": "St.Moritzersee_T-Mooring", | ||
386 | "type": "dataset", | 410 | "type": "dataset", | ||
387 | "url": "https://doi.org/10.25678/0000kk/", | 411 | "url": "https://doi.org/10.25678/0000kk/", | ||
388 | "version": null | 412 | "version": null | ||
389 | } | 413 | } |