NAAD domain

The NAAD (North Atlantic Atmospheric Downscaling) provides a 40-year 3D hindcast of the North Atlantic atmosphere (10°N-80°N) at 14 km (HiRes) and 77 km (LoRes) spatial resolution with 50 levels in the vertical (from approximately 10-12 m above the ocean surface up to 50 hPa), performed with a regional setting of the WRF-ARW 3.8.1 model for the period from January 1979 to December 2018 and forced by ERA-Interim as a lateral boundary condition. The main focus of the NAAD is the long-term atmospheric mesoscale dynamics over the ocean. The NAAD can be also effectively used for forcing ocean and wave models to estimate the impact of the mesoscale activity in the lower atmosphere. The dataset provides a variety of surface and free atmosphere parameters at the model levels.

WRF configuration of the NAAD
HiRes LoRes
Model settings
Model WRF-ARW 3.8.1
Dynamical core Nonhydrostatic Hydrostatic
Domain settings
Horizontal Resolution 14 km 77 km
Vertical Resolution 50 hydrostatic pressure-sigma levels (50 hPa top)
Timestep (RK3) 30 s 240 s
Main physics options
Microphysics WSM6 WSM5
Convection Kain-Fritsch
PBL YSU
Surface layer MM5
Radiative transfer RRTMG
Land surface model Noah LSM
Boundary conditions
Initial & boundary conditions ERA-Interim
SST ERA-Interim (every 6 hr)
Data assimilation Spectral nudging from PBL (longer that 1100 km)

The computational grid of the NAAD has 50 vertical levels, 15 of which are located below 850 hPa. This provides approximately 6-15 levels within the PBL (depending on the season and location). The height of the lowest level is around 10-12 m above the ocean surface. See the table below.

Model levels
model
level		 Terrain
following
sigma
level		 model
level		 Terrain
following
sigma
level		 model
level		 Terrain
following
sigma
level
1 1 18 0.7889637 35 0.1736677
2 0.997 19 0.7586183 36 0.1536199
3 0.993 20 0.7029784 37 0.1349515
4 0.987 21 0.6504962 38 0.117587
5 0.980 22 0.6010224 39 0.1017257
6 0.973 23 0.5544136 40 0.08734228
7 0.966 24 0.510532 41 0.07429918
8 0.960 25 0.4692457 42 0.06247147
9 0.952 26 0.4304279 43 0.05174589
10 0.944 27 0.393957 44 0.04201975
11 0.934 28 0.3597165 45 0.03319991
12 0.925 29 0.3275948 46 0.02520193
13 0.915 30 0.2974847 47 0.01794922
14 0.900 31 0.2692837 48 0.01137233
15 0.88 32 0.2428935 49 0.005408296
16 0.8496546 33 0.2182202 50 0.
17 0.8193091 34 0.1951736
Design and development: Alexander Gavrikov, Andrey Muratov; Support: naad-at-ocean.ru; 2024
21 Mar 2022
The pressure variable has been added

The 3D pressure variable on model levels has been added to NAAD HiRes/LoRes. The list of all variables is available in the section Variables.

8 Mar 2022
The height variable has been added

The 3D height variable on model levels has been added to NAAD HiRes/LoRes. The list of all variables is available in the section Variables.

25 Jun 2020
The NAAD HiRes (14 km) has been uploaded

All variables listed in the Variables section are available for download.

14 Jun 2020
Open access

Access to the NAAD data is now available through the Data Access Protocol (DAP). Details are in the Download section.

1 Jun 2020
The NAAD LoRes (77 km) has been uploaded

All variables listed in the Variables section have been uploaded for the LoRes (77 km) run of the NAAD dataset. The NAAD HiRes (14 km) is currently uploading. Access to the data will be provided within a few weeks.

21 Apr 2020
Revised list of variables provided

The short list of potentially the most demanded variables is now in the Variables section both for LoRes and HiRes datasets. It will soon be available for download. The long list will be provided later.