Best-supported values with reliability grades · Underconstrained variables
3.1 Geometry and Baseline Statistics
Parameter
Symbol
Value
Source
Reliability
Upstream mainstem length at Óbidos
\(L_B\)
≈ 3 869 km
UNH/GRDC [1]
A
Mean discharge at Óbidos
\(\bar{Q}\)
≈ 1.76 × 10⁵ m³/s
UNH/GRDC [1]
A
Annual harmonic amplitude
\(B_1\)
≈ 6.4 × 10⁴ m³/s
Verifier fit (1928–1996)
A/B
Semiannual harmonic amplitude
\(B_2\)
≈ 8.3 × 10³ m³/s
Verifier fit (1928–1996)
A/B
Amplitude ratio
\(r = B_2/B_1\)
≈ 0.13
Derived
A/B
Effective phase difference
\(\delta\)
≈ 0.9 rad
Verifier fit
A/B
Reliability key:A = direct dataset summary or peer-reviewed measurement;
A/B = peer-reviewed analysis or reproducible derived quantity;
B = foundational but dated, or limited modern specificity.
Required for timing/attenuation; validated against multi-data-stream obs.
MGB-IPH / WRR [3]
A/B
3.4 Threshold Evidence (Historical)
Parameter
Value / Statement
Source
Reliability
Direct discharge reconnaissance
Context and baseline; notes need for many more measurements
USGS Circ. 552 [4]
B
4. Underconstrained Variables
These items prevent upgrading "PROVISIONAL" entries to "PASS":
Annual-by-annual fitted \((r_y, \delta_y)\) at Óbidos and Manaus from
long daily/monthly series. Needed to compute regime occupancy
\(P(\text{two-maxima})\). Dependency: F-1,
CL-3 upgrade gate.
Explicit rainfall harmonic fits for defined North-lump / South-lump masks
from a chosen gridded rainfall product (GPCC/TRMM/GPM), yielding
\(A_{ik}, \phi_{ik}\) and their interannual drift.