Developer	Type	Geometry Req.	Threshold Req.	Temporal Req.	Region	DIO/Reference
A16,A23,A24	Brands et al	Condition	> 1500 km	Both Relative and Absolute IVT: 95th(A16)/90th(A23)/90th(A24) percentile at point of detection, 90th/85th/85th percentile along the AR structure, consider all months for threshold calculation with a min threshold of 240/500/250 kgm-1s-1. Spatial tracking guided by vector IVT.	Time slice	150°W to 30°E 30°N to 62°N	10.1007/s00382-016-3095-6
A1	Gershunov et alb	Condition and Track	>= 1500km long	Absolute: 250kgm-1s-1 IVT 1.5cm IWV	Time stitching -18 hours (3 time steps for 6 hourly data)	Western U.S.	10.1002/2017GL074175
A2	Goldensonb	Condition	> 2000km long and < 1000km wide Object recognition	Absolute: 2cm IWV	Time slice	Western U.S.	10.1175/JCLI-D-18-0268.1
A17	Gorodetskaya et al	Condition	IWV > thresh. at the coast (within defined longitudinal sector) and continuously at all latitudes for ≥ 20° equatorward (length > 2000 km), within ± 15° longitude sector (width of 30° ~ 1000 km at 70°S; requirement of meridional extent)	Relative: aZN using IWV adjusted for reduced tropospheric moisture holding capacity at low temperatures (ARcoeff = 0.2)	Time slice	Polar (East Antarctica)	10.1002/2014GL060881
A3	Guan and Waliserbc	Condition	Length >2000km and length width ratio >2; Coherent IVT direction within 45° of AR shape orientation and with a poleward component	Relative: 85th percentile IVT; Absolute min requirement designed for polar locations: 100kgm-1s-1 IVT	Time slice	Global	10.1002/2015JD024257 10.1175/JHM-D-17-0114.1 tracker code
A4	Hagos et al. b (PNNL1)	Condition	Dependent on threshold requirements to determine footprint; > 2000 km long and < 1000 km wide	Absolute: 2cm IWV 10ms-1 wind speed	Time slice	Western U.S.	10.1175/JCLI-D-14-00567.1
A36	Kashinath et al. f (ClimateNet)	Condition	Deep learning based segmentation. Trained on ~500 expert labelled images	Threshold free; input fields are IWV, U850, V850, SLP	Time slice	Global	10.5194/gmd-2020-72
A27	Krinitsky et al. (SAIL)	Condition	Geometry reqirements Length >= 250km; Length-to-width >=5; Length is estimated along the "ridge" taking IVT into account. Width is the median of widths estimated in each point of AR ridge.	Relative: IVT-IVT_RM >_ 100. IVT_RM is climatological IVT running mean with 20-day windows	Time slice	Global	Experimental
A18	Lavers et al.	Condition	4.5° latitude movement allowed	Relative: ~85th percentile determined by evaluation of reanalysis products	Time slice	UK, Western US	10.1029/2012JD018027
A5	Leung and Qianb (PNNL2)	Track	Moisture flux has an eastward or northward component at landfall; tracks originating north of 25N and east of 140W are rejected	Absolute: mean IVT along track > 500 kgm-1s-1 and IVT at landfall > 200 kgm-1s-1; grid points up to 500km to the north and south along the AR tracks are included as part of the AR if their mean IVT > 300 kgm-1s-1	Time slice	Western U.S.	10.1029/2008GL036445
A6,A7	Lora et al.b	Condition	Length >= 2000km	v1: Relative : IVT 100kgm-1s-1 above climatological area means for N. Pacific; v2:Relative/Absolute : IVT 225 kgm-1s-1 above time/latitude dependent threshold using 30-day running mean and zonal average of IWV	Time slice	v1 Global (A6) v1 North Pacific (A7) v2 (Global)	10.1002/2016GL071541 10.1016/j.epsl.2020.116293
A25,A26	Mahesh and O'Brien (CASCADE)	Condition	Convolutional neural network to replicate ARTMIP mean	Threshold-free; IVT(A25) and IWV (A26) is the input, output is probability of AR presence	Time slice	Global	Experimental
	Mahoney et al.	Condition and Track	Length >= 1500km, Width <=1500km	Absolute: ARDT-IVT 500kgm-1s-1 for SEUS.	See Wick	Southeast U.S.	10.1175/MWR-D-15-0279.1 (uses Wick)
A19	Mundhenk	Condition	>1400km length, aspect ratio 1:4, lat limit >16N/S, axis orientation based on IVT	Relative IVT percentiles and/or anomalies both temporal and spatial	Time slice	Global	10.1175/JCLI-D-15-0655.1
A20	Muszynski et al. (ML_TDA)	Condition	Topological analysis and machine learned	Threshold-free	N/A	Western U.S., adaptable to other regions	10.5194/gmd-12-613-2019
A32	O'Brien et al. (teca_bard_v1.01 = CASCADE_bard_v1)	Condition	eMinimum area	eRelative threshold (based on spatial percentile for each timestep). An inverted Gaussian filter is applied at the equator to damp out the ITCZ	Time slice	Global	10.5194/gmd-13-6131-2020
A33	PanLu	Condition	1) Length>2000km; 2) Length-Width ratio>2; 3) sum of turning angle<360; 4) percentage within tropics < 95%; 5) 50% < percentage within tropics < 95% or percentage with IVT direction smaller than 15 degrees <50%	Two relative thresholds. Local threshold: smoothed 85% quantile IVT field using the Gaussian kernel density smoothing technique; regional threshold: the 80% quantile of IVT for all grids within 80N and 80S.	Time stitching: last for at least 18 hours	East Asia & Global	10.1029/2018WR024407 10.1029/2020GL089477
A8	Payne and Magnusdottirbc	Condition	Length > 1200km, landfalling only	Relative: 85th Percentile of maximum IVT (1000-500mb) Absolute: IWV >2cm, 850mb wind speed > 10m/s	Time stitching (12-hour minimum)	Western U.S.	10.1002/2015JD023586 10.1002/2016JD025549
	Ralph et al.	Condition	Length >= 2000km, Width <= 1000km	Absolute: IWV 2cm	Time slice	Western U.S.	10.1175/1520-0493(2004)132
A9,A31	Ramos et al.bc; Blamey et al.*	Condition	Detected for reference meridians, length >=1500km (1800km*), latitudinal movement <4.5°N	Relative: IVT 85th percentile (1000-300mb)	Time slice, but 18-hour minimum for persistent ARs	Western Europe, South Africa*, adaptable to other regions	10.5194/esd-7-371-2016 10.1175/JHM-D-17-0111.1
A34	Reid et al.	Condition	Length > 2000km; Length-Width ratio > 2; orientation angle >10°	= Absolute. IVT > 250 kg/m/s; IVT > 500 kg/m/s	Time slice	Global	10.1029/2020JD032897
A10	Rutz et al.b	Condition	Length >= 2000km	Absolute: IVT (surface to 100mb) = 250kgm-1s-1	Time slice	Global, low value on tropics	10.1175/MWR-D-13-00168.1
A30	Shearer et al.(AR-CONNECT)	Track	Object identification	Absolute: Absolute: IVT thresholds used = 700 for seeding, 300, for region growing	Time stitching, minimum 24-hour period	Global weighted centroid of AR event must be outside tropics (23.25 N - 23.25 S)	10.1029/2020JD033425
A11, A12, A13	Sellars et al.b (CONNECT)	Track	Object identification	Absolute: IVT, thresholds tested = 300 (A11), 500 (A12), 700 (A13) kgm-1s-1	Time stitching, minimum 24-hour period	Global	10.1002/2013EO320001 10.1175/JHM-D-14-0101.1
A14	Shields and Kiehlb	Condition	Ratio 2:1, length to width grid points min 200km length; 850mb wind direction from specified regional quadrants, landfalling only	Relative: aZN moisture threshold using IWV; Wind threshold defined by regional 85th percentile 850mb wind magnitudes	Time slice	Western U.S. Iberian Peninsula, UK, adaptable but regional specific	10.1002/2016GL069476 10.1002/2016GL070470
A15	TEMPESTb	Track	dLaplacian IVT thresholds most effective for widths >1000km; cluster size minimum = 120000km2	dIVT >=250kgm-1s-1	Time stitching	Global, but latitude >=15°	10.1029/2020JD033421 10.5194/gmd-10-1069-2017 10.1029/2019JD031977 10.1029/2020JD033421
A21	Viale et al.	Condition	Length >2000km (>1500km north of 35°S) and length-width ratio>2; Coherent IVT direction within 45° of AR mean direction and with a poleward component	Relative: 85th percentile IVT; Absolute min requirement designed for subtropical locations: 100kgm-1s-1 IVT; a frontal zone intercept or locate south (up to 50 km), i.e., mag. of the horizontal gradient of the 1000-850hPa thickness > 5 m 100 km-1)	Time slice	Southwestern South America	10.1175/JHM-D-18-0006.1
A22	Walton et al.	Condition and Track	Length >= 2000 km	Relative: IVT > 250 kg/m/s + daily IVT climatology	Time stitching, minimum 24-hour period	Western U.S.	Experimental
	Wick et al.	Condition and Track	>=2000km long, <= 1000km wide object identification involving shape and axis	Absolute: ARDT-IWV >2cm	Time slice and stitching	Regional	10.1109/TGRS.2012.2211024
A28,A29	Wille et al.	Condition	Length > 20° (2000 km) equatorward with no breaks. Defined as AR landfall if AR shape overlaps a land grid cell.	Relative > 98th percentile IWV(A28) or vIVT(29) based on monthly climatological means	Time slice	Polar: Antarctic(37.5o-78oS; Arctic(37.5o-80oN	Antarctic 10.1029/2020JD033788 Arctic: Experimental
A35	Xu et al. (IPART)	Condition and Track	Length >= 1500 km, area in range [50*10^4, 1800*10^4 km^2], L/W ratio>=2, isoperimetric quotient < 0.7, centroid latitude > 20 N, < 80 N.	Threshold free;Select transient IVT plumes standing out from a temporal scale of 8 days;Spatial scale of ~ 1000 km	Time slice and stitching	Northern Hemisphere	10.5194/gmd-13-4639-2020
A37	Zhang, Tung, & Cleveland g (Purdue)	Multifactorial Conditions and Track	(Length >= 1500, 1800, OR 2000 km) AND (Length/average Width >= 2)	Relative: (75th, 85th, OR 95th monthly percentile applied at every gridpoint, in ENSO neutral and weak ENSO years)   (IVT, IWV, OR IVT+IWV)	(Persistent Duration >=12, 18, OR 24 hours) AND (Break < 24 hours)	Regional: West-Coast landfalling region: located between 33-48.5N and 124.375-114.375W; Midwest region is between 37-47N and 94-84W	10.1029/2020JD033667

^aZN relative threshold formula: Q >= Q_{zonal_mean} + AR_coeff (Q_zonalmax – Q_zonamean) where Q = moisture variable, either IVT (kg m^-1s^-1) or IWV(cm). AR_coeff = 0.3 except where noted (Zhu and Newell, 1998). The Gorodetskaya method uses Q_sat, where Q_sat represents maximum moisture holding capacity calculated based on temperature (Clausius-Clapeyron), an important distinction for polar ARs. Additional analysis on the ZN method can be found in Newman et al., 201

^bMethods used in a 1-month proof-of-concept test (Section 5). These methods are assigned an algorithm id, i.e. A1, A2, etc.

^cThese 1-month proof-of-concept methods apply a percentile approach to determining ARs. A3 and A8 applied the full MERRA2 climatology to compute percentiles. A9, applied the Feb 2017 climatology for this test only. For the full catalogues, A9 will apply extended winter and extended summer climatologies to compute percentiles. Please refer to individual publications (DOI reference column in this table) for climatologies used in earlier published studies by each developer. The climatology used to compute percentile is often dependent on the dataset (re-analysis or model data) being used.

^dd Tempest contains both an absolute threshold (typically set at IVT>250) and a relative threshold (which uses a local Laplacian of IVT, typically set at del^2 IVT < -50k).

^eThe O’Brien et al. Bayesian AR Detector (BARD) algorithm runs 1,024 AR detectors simultaneously. Percentile threshold, minimum area, and filter latitude width are all sampled from a posterior distribution that is designed to optimize global AR counts relative to a dataset of AR counts from a set of experts.

^fThe DL model presented in the paper and the one used to produce the catalogue use slightly different architectures (DeepLab3+ vs CGNet)

^gThe Purdue indices consist of 81 indices for the land-falling West-Coast ARs and 81 indices for the inland Midwest ARs.