Update README.md
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README.md
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@@ -41,20 +41,20 @@ More detailed information about the new parameters introduced with AIFS Single v
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| Short Name | Name | Units | Component Type | Lev.Type |
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|:----------:|:----:|:-----:|:--------------:|:--------:|
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| swl1 | Volumetric soil water layer 1 |
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| swl2 | Volumetric soil water layer 2 |
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| stl1 | Soil temperature level 1 |
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| stl2 | Soil temperature level 2 |
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| 100u | 100 metre U wind component |
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| 100v | 100 metre V wind component |
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| ssrd | Surface short-wave (solar) radiation downwards |
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| strd | Surface long-wave (thermal) radiation downwards |
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| tcc | Total cloud cover |
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| hcc | High Cloud Cover |
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| mcc | Medium Cloud Cover |
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| lc | Low cloud cover |
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| ro | Runoff |
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| sf | Snowfall |
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#### Changes to existing parameters
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@@ -171,22 +171,22 @@ to the fact that for AIFS Single v0.2.1 we used just operational-analysis data f
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release we have done the fine-tunning from 2016 to 2022.
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The other important change in the fine-tuning stage is that for AIFS Single v0.2.1 after the 6hr model training the
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optimiser was not restarted (ie. rollout was done with the minimal lr of
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that restarting the optimiser for the rollout improves the model's performance. For the operational-fine tuning rollout
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stage, the learning rate cycle is restarted, gradually decreasing to the minimum value at the end of rollout.
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<!-- This relates heavily to the Technical Specifications. Content here should link to that section when it is relevant to the training procedure. -->
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- **Pre-training**: It was performed on ERA5 for the years 1979 to 2022 with a cosine learning rate (LR) schedule and a
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total of 260,000 steps. The LR is increased from 0 to
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minimum of
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- **Fine-tuning**: The pre-training is then followed by rollout on operational real-time IFS NWP analyses for the years
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2016 to 2022, this time with a local learning rate of
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increase per epoch. In this second stage the warm up period of the optimiser is 100 steps to account for shorter length
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of this stage. Optimizer step are equal to 7900 ( 12 epoch with ~630 steps per epoch).
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As in the previous version of aifs-single for fine-tuning and initialisation of the model during inference, IFS fields
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are interpolated from their native O1280 resolution (approximately
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#### Training Hyperparameters
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| Short Name | Name | Units | Component Type | Lev.Type |
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|:----------:|:----:|:-----:|:--------------:|:--------:|
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| swl1 | Volumetric soil water layer 1 | \\(m^3 m^{-3}\\) | HRES | sfc |
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| swl2 | Volumetric soil water layer 2 | \\(m^3 m^{-3}\\) | HRES | sfc |
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| stl1 | Soil temperature level 1 | \\(K\\) | HRES | sfc |
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| stl2 | Soil temperature level 2 | \\(K\\) | HRES | sfc |
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| 100u | 100 metre U wind component | \\(m s^{-1}\\) | HRES | sfc |
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| 100v | 100 metre V wind component | \\(m s^{-1}\\) | HRES | sfc |
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| ssrd | Surface short-wave (solar) radiation downwards | \\(J m^{-2}\\) | HRES | sfc |
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| strd | Surface long-wave (thermal) radiation downwards | \\(J m^{-2}\\) | HRES | sfc |
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| tcc | Total cloud cover | \\((0 - 1)\\) | HRES | sfc |
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| hcc | High Cloud Cover | \\((0 - 1)\\) | HRES | sfc |
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| mcc | Medium Cloud Cover | \\((0 - 1)\\) | HRES | sfc |
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| lc | Low cloud cover | \\((0 - 1)\\) | HRES | sfc |
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| ro | Runoff | \\(m\\) | HRES | sfc |
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| sf | Snowfall | \\(m\\) of water equivalent | HRES | sfc |
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#### Changes to existing parameters
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release we have done the fine-tunning from 2016 to 2022.
|
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|
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The other important change in the fine-tuning stage is that for AIFS Single v0.2.1 after the 6hr model training the
|
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+
optimiser was not restarted (ie. rollout was done with the minimal lr of \\(3 × 10^{-7}\\)). For this release we have seen
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that restarting the optimiser for the rollout improves the model's performance. For the operational-fine tuning rollout
|
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stage, the learning rate cycle is restarted, gradually decreasing to the minimum value at the end of rollout.
|
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|
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<!-- This relates heavily to the Technical Specifications. Content here should link to that section when it is relevant to the training procedure. -->
|
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|
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- **Pre-training**: It was performed on ERA5 for the years 1979 to 2022 with a cosine learning rate (LR) schedule and a
|
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+
total of 260,000 steps. The LR is increased from 0 to \\(10^{-4}\\) during the first 1000 steps, then it is annealed to a
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minimum of \\(3 × 10^{-7}\\). The local learning rate used for this stage is \\(3.125 × 10^{-5}\\).
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- **Fine-tuning**: The pre-training is then followed by rollout on operational real-time IFS NWP analyses for the years
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+
2016 to 2022, this time with a local learning rate of \\(8 × 10^{−7}\\), which is decreased to \\(3 × 10^{−7}\\). Rollout steps
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increase per epoch. In this second stage the warm up period of the optimiser is 100 steps to account for shorter length
|
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of this stage. Optimizer step are equal to 7900 ( 12 epoch with ~630 steps per epoch).
|
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|
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As in the previous version of aifs-single for fine-tuning and initialisation of the model during inference, IFS fields
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are interpolated from their native O1280 resolution (approximately \\(0.1°\\)) down to N320 (approximately \\(0.25°\\)).
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#### Training Hyperparameters
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