[126] | 1 | .. + |
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| 2 | .. |
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| 3 | .. |
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| 4 | .. DESCRIPTION |
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| 5 | .. =========== |
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| 6 | .. |
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[127] | 7 | .. description |
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[126] | 8 | .. |
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| 9 | .. TODO |
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| 10 | .. ==== |
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| 11 | .. |
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[127] | 12 | .. (July 1983 to December 2009 at the time of writing), ... not anymore true |
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[126] | 13 | .. |
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| 14 | .. EVOLUTIONS |
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| 15 | .. ========== |
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| 16 | .. |
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| 17 | .. $Id$ |
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| 18 | .. |
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| 19 | .. $URL$ |
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| 20 | .. |
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[146] | 21 | .. - fplod 20120229 |
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| 22 | .. |
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| 23 | .. * add meta robots constraints |
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| 24 | .. |
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[139] | 25 | .. - fplod 20120222 |
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| 26 | .. |
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| 27 | .. * links and associated text are now defined in :ref:`prolog.rst` |
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| 28 | .. |
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[137] | 29 | .. - jv 20120222 |
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| 30 | .. |
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| 31 | .. * typos |
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| 32 | .. |
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[127] | 33 | .. - fplod 20120219 |
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| 34 | .. |
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| 35 | .. * fix links, add bold |
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| 36 | .. |
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[126] | 37 | .. - fplod 20120217 |
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| 38 | .. |
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| 39 | .. * creation from description.odt |
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[127] | 40 | .. transform to ReST using odt2sphinx + hand correction (diacritical, |
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[126] | 41 | .. ponctuations, short lines, links !!) |
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| 42 | .. |
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| 43 | .. - |
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| 44 | |
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[146] | 45 | .. meta:: |
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| 46 | :robots: noindex,nofollow,noarchive |
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| 47 | |
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[126] | 48 | .. _description: |
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| 49 | |
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| 50 | Description |
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| 51 | =========== |
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| 52 | |
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| 53 | How are TropFlux fluxes estimated ? |
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[127] | 54 | +++++++++++++++++++++++++++++++++++ |
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[126] | 55 | |
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[127] | 56 | * **The TropFlux heat and momentum fluxes are estimated from the COARE v3 |
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| 57 | algorithm** (`Fairall et al. 2003 <http://dx.doi.org/10.1175/1520-0442(2003)016%3C0571:BPOASF%3E2.0.CO;2>`_), |
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| 58 | arguably one of the most suited algorithm for fluxes estimations in the |
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| 59 | tropical regions. |
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| 60 | This algorithm requests surface meteorological parameters (10m-winds, |
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| 61 | 2m-air and sea temperature, 2m-air relative humidity) and downward |
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[126] | 62 | radiative (shortwave and infrared fluxes) as input parameters. |
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| 63 | |
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[127] | 64 | * The analysis of various data sources shows that, except for shortwave |
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| 65 | radiation, ERA-I data generally displays the best agreement to the |
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[139] | 66 | |gtma|_ |
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[127] | 67 | data, despite systematic biases and underestimated variability |
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[186] | 68 | |pkbetal2012|_. |
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[139] | 69 | The |isccpbrowse|_ provides the best shortwave data. |
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[127] | 70 | **TropFlux hence uses bias and amplitude corrected ERA-I (10m-winds, 2m-air |
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| 71 | and sea temperature, 2m-air relative humidity and downward radiative |
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| 72 | fluxes) and ISCCP (shortwave radiation) fluxes.** |
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[126] | 73 | All bias corrections are derived on the basis of comparisons with |
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[127] | 74 | the |
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[139] | 75 | |gtma|_ |
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[127] | 76 | data, and are described in detail in |
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[186] | 77 | |pkbetal2012|_. |
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[126] | 78 | |
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[127] | 79 | * **An additional climatological surface temperature-dependent gustiness |
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| 80 | is applied to wind speed, in order to account for unresolved (sub-daily and subgrid-scale) variability.** |
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[126] | 81 | |
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| 82 | * Since ISCCP shortwave data |
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[127] | 83 | is not updated on a regular basis, we provide an alternative shortwave |
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| 84 | flux estimate that is less accurate, but available until present. |
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| 85 | This estimate uses the ISCCP shortwave climatology plus anomalies that are |
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[139] | 86 | linearly related to |noaaolr|_ the anomalies with respect to the seasonal cycle. |
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[127] | 87 | Such an estimate is almost as good as ISCCP in deep atmospheric convection |
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| 88 | regions such as the ITCZ or Indo-Pacific warm pool. |
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| 89 | It does not perform as well as ISCCP in regions of low clouds such as the |
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| 90 | eastern equatorial Pacific and Atlantic oceans, but is in any case better |
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[137] | 91 | than most available re-analyses in those regions |
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[186] | 92 | (|pkbetal2012|_). |
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[127] | 93 | The net surface shortwave that is provided in TropFlux data files is based |
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| 94 | on ISCCP data over the entire period for which it is available (July 1983 |
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| 95 | to December 2009 at the time of writing), with a linear transition to |
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| 96 | OLR-derived shortwave over a three months window at the edges of the |
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[126] | 97 | ISCCP-availability window. |
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