Incoming shortwave radiation at 47 m
Half-hourly incoming shortwave radiation at 47 m on the CH-LAE tower, 2004-2025, gap-filled to completeness. The file is 01_METEO_SW_IN_GAPFILLED_2004-2025 (parquet and CSV): 385,728 records on a continuous 30-minute middle-timestamp index (named TIMESTAMP_MIDDLE in the file) in local time (UTC+1, no daylight saving), from 2004-01-01 00:15 to 2025-12-31 23:45.
The interactive dashboard summarises the product on one page: coverage and provenance, seasonality, distributions, extremes and trends, with a table view behind every chart. It is standalone and works offline.
Method, evidence and checks:
01_METEO_SW_IN— builds the product: the merge of the two screenings, the 2012 corrections, the nighttime offset, the gap-filling, and the evidence that the record is homogeneous across both hardware changes.RADIATION_SENSOR_CONTINUITY— compares four radiation sensors and attributes every level change in the record to a particular instrument.Meteo_Product_Chain— where this product sits in the chain.TA,PPFD_INandVPDall read it.
This series needs no homogenisation. The same sensor was read through the same calibration across the January 2016 acquisition change, and the December 2021 replacement of the radiometer did not move the level either. There is a single value column and no _HOMOGENIZED counterpart.
Two things a user should still know about are described under Known limitations: a slow departure of the sensor from its references from 2013, and a level change in the MeteoSwiss series used to fill the gaps.
Columns
Every one of the 385,728 records carries a value, and the flag is defined everywhere.
01_METEO_SW_IN_GAPFILLED_2004-2025.
| column | unit | description |
|---|---|---|
SW_IN_T1_47_1_gfXG |
W m-2 | Incoming shortwave radiation, gaps filled. Complete, non-negative, exactly zero at night. |
FLAG_SW_IN_T1_47_1_ISFILLED |
- | Whether the value was measured, and if not, which method produced it. |
FLAG_SW_IN_T1_47_1_ISFILLED
Filter on == 0 for measured records. The series is complete, so every other code marks a modelled value. Code 4 is not used.
| code | meaning | records | share |
|---|---|---|---|
| 0 | observed | 351,726 | 91.2 % |
| 1 | daytime gap, filled by the XGBoost model | 17,411 | 4.5 % |
| 2 | daytime gap, filled by the timestamp-only fallback model | 697 | 0.2 % |
| 3 | nighttime gap, set to zero by physics | 15,894 | 4.1 % |
Code 3 is not an estimate: the sun is below the horizon and the value is zero by physics. Counting codes 0 and 3 together as not modelled raises the non-modelled share to 95.3 %.
Fill quality is not uniform across the record. Until 2018 two independent radiation measurements drive the model: NABEL at 49 m on the same tower, and MeteoSwiss Lägern 2.5 km away. From 2019 only Lägern remains, so the fills of the later period lean on the more distant sensor. Code 2 marks the few half-hours where neither driver was available.
Coverage
The tower measurement begins on 2005-09-14 11:15, the date the radiometer was wired to the tower logger. Everything before that is modelled.
| year | measured | why |
|---|---|---|
| 2004 | 0 % | before the radiometer was connected to this logger |
| 2005 | 30 % | the record begins on 14 September |
| 2012 | 93 % | logger clock error, power-supply failure and storm damage |
| 2016 | 94 % | the January outage during which the logger was replaced |
The 2012 faults are the largest interruption inside the measured period. A logger clock error shifted one block of August 2012 by 15.5 hours; a tower power-supply failure in late July and August, and storm damage in late October and November, left records that could not be repaired. The clock error was corrected, the other two periods were removed, and all of it was gap-filled. Notebook 01 carries the day-by-day evidence.
How the gaps were filled
Daytime gaps are filled by an XGBoost model, separately for 2004-2018 and 2019-2025. The split is not at a hardware change: it is where the NABEL sensor stops, and therefore where the model loses a driver. Training one model across that boundary would let records on one side be predicted by a relationship fitted mostly on the other.
Both drivers enter the model as measured, never gap-filled, so the target is never used to predict itself. Nighttime gaps are set to zero rather than modelled. The exported series is always the tower sensor; a reference is a driver and never overwrites a measured value.
Known limitations
The sensor departs from its references by a few per cent from 2013. From 2013 the tower radiometer reads about 3 % high relative to NABEL at 49 m, MeteoSwiss Lägern, and the co-located PAR sensor, all three at once, which places the change on this instrument rather than on any of them. It develops over about three years rather than stepping at a date, no maintenance record covers it, and the fieldbook records no calibration of this radiometer between its installation in 2005 and its removal in 2021. It is within the field uncertainty of a pyranometer of this class over that interval and is not corrected, because a correction could neither be applied at a boundary nor justified by a known fault. Analyses comparing the middle of the record against its beginning should allow for a few per cent on that account.
The MeteoSwiss series used to fill the gaps changed level in October 2010.
SW_IN_LAE_MS, the gap-filling driver and the only one after 2018, steps by about 5 % on 6 October 2010, when that station’s radiation instrumentation was rebuilt. This is a property of the reference, not of the tower: the two tower sensors and NABEL’s all step against it together and not against each other. It does not degrade the fills, since a driver supplies the state of the sky and a scale change does not alter which half-hours were cloudy. It does mean that a difference between this product and MeteoSwiss Lägern must not be read as evidence about the tower across that date.Nighttime values are exactly zero, not measurements. A pyranometer reads a small drifting offset at night. It is an instrument offset rather than radiation, and it was removed per day before gap-filling, which sets every measured nighttime record to exactly zero. Analyses of instrument noise or of the offset itself must go back to the screened database series.
2004 and most of 2005 are entirely modelled. They precede the measurement and rest on MeteoSwiss Lägern alone, which itself begins on 1 February 2004. These are the least constrained parts of the record.
What the January 2016 acquisition change did
Nothing measurable. It is recorded here because the same changeover moved TA_T1_47_1 by 1.3 °C.
TA changed sensor and conversion at once; shortwave radiation changed neither. Every surviving logger program, three CR10X programs spanning 2005-2006 and the CR1000 program installed at the changeover, measures the same Kipp & Zonen CNR1, serial number 020484, on a 25 mV differential channel at multiplier 99.7009 and offset 0. That multiplier is the reciprocal of the sensitivity of that instrument. Replacing the logger changed how the voltage was digitised and nothing about what it meant.
The data agree. Across 2016 every ratio among the three shortwave sensors changes by less than the same measurement changes in an ordinary year; the largest is 1.4 %, and it belongs to the pair that does not involve the tower at all. Notebook 01 asserts this on every run, so a future change to the product that reintroduced a step would fail rather than export quietly.
The radiometer itself was replaced in December 2021, a CNR1 giving way to a CNR4 with a sensitivity a third larger. That boundary coincides with the change of screening software, so the two possible causes of a step cannot be separated. Neither produces one.